Technical information about the '76 to '79 Cadillac Seville. Subjects are "EFI Diagnosis", "'76 - '79 body parts", "Frame diagram" and "Electrical troubleshooting".
Important Safety Notice |
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Proper service and repair is important to the safe, reliable operation of all motor vehicles. The service procedures recommended by Cadillac and described in this service manual are effective methods of performing service operations. Some of these service operations require the use of tools specially designed for the purpose. The special tools should be used when and as recommended.
It is important to note that this manual contains various Warnings, Cautions and Notes which should be carefully read in order to minimize the risk of personal injury to service personnel or the possibility that improper service methods will be followed which may damage the vehicle or render it unsafe. It is also important to understand that these Warnings, Cautions and Notes are not exhaustive. Cadillac could not possibly know, evaluate and advise the service trade of all conceivable ways in which service might be done or of the possible hazardous consequences of each way. Consequently, Cadillac has not undertaken any such broad evaluation. Accordingly, anyone who uses a service procedure or tool which is not recommended by Cadillac must first satisfy himself thoroughly that neither his safety nor vehicle safety will be jeopardized by the service method he selects.
How to use this book |
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NOTE
The first three pages contain general information about electrical troubleshooting, symbols, and fuse and bulb information. Read these pages to be sure you know the meaning of the symbols used in this book.
Each Wiring Diagram shows when and how the circuit gets its power, what the current path is to the circuit components, and where the components are grounded. The component name is usually found to the right of each component (underlined), and some important operating information is given. Wire gauge and colors are also listed.
The Text Page contains four pieces of information: Component Location (given in chart form); Troubleshooting Hints, suggested short-cuts to find the problem (given in effect-cause form); Figures, which give a visual location for connectors and components; and, for more complex systems, Circuit Operation, a description of the special features of the circuit.
The Ground Page gives a detailed view of complex car ground points.
01 - Troubleshooting |
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1. Check the Complaint : Operate the problem circuit yourself (or watch the customer operate it) to be sure you understand what's wrong. Don't waste time fixing part of the problem!
2. Read the Wiring Diagram : Study the diagram to understand how the circuit is supposed to work. Read the detailed description added in complex diagrams.
3. Find the Problem : Use the Troubleshooting section with each circuit.
4. Make the Repair.
5. Test the Repair: Operate the repaired system in all modes to be sure the whole problem is fixed - not just part.
TROUBLESHOOTING TOOLS
Test Light: a 12-volt light bulb with a set of test leads.
Uses: Voltage Check, Short Check
Figure 1-1 - Test Light
Self-Powered Test Light: a light, battery, and set of test leads wired in series.
Uses: Continuity Check, Ground Check
Figure 1-2 - Self-Powered Test Light
Jumper Wire: a circuit breaker with a length of wire and clips on each end.
Uses: Bypassing Open Circuits and Loose Connections.
WARNING: Never use a jumper wire across any load (motors, ect.). This direct battery short may cause injury or fire.
Figure 1-3 - Jumper Wire
VOLTAGE CHECK:
1. Connect one lead of test light to a known good ground or negative (-) battery terminal.
2. Connect other test light lead to connector or component terminal. Bulb lights when voltage is present.
Figure 1-4 - Voltage Check
SHORT CHECK (blown fuse):
1. Remove fuse and disconnect all loads.
2. Connect test light across fuse terminals.
3. Beginning near the fuse block, move the harness from side to side while watching the test light.
4. Test Light ON: Short to ground in the wiring. Somewhere in that area the wire insulation has worn away and circuit is grounding.
Figure 1-5 - Short Check
CONTINUITY CHECK:
CAUTION: Be sure no voltage is present in circuit during this test.
Connect one lead of self-powered test light at one end of the circuit, and the other lead at the other end. Test light glows if there is continuity.
Switches can be checked in the same way.
Figure 1-6 - Continuity Check
GROUND CHECK
CAUTION: Be sure no voltage is present in circuit during this test.
Connect one lead of self-powered test light to a known good ground, and the other lead to the wire in question.
- Light ON: ground is good
- Light OFF: no ground
GENERAL TROUBLESHOOTING HINTS
If several unrelated circuits fail at the same time, chances are the power (fuse) or ground circuit is bad.
Use the Fuse Information to find what circuits are powered through each fuse.
Use the Ground Page to find which circuits have a common ground.
NOTE: Ground page shows only complex eyelet grounds. Circuits with single or component grounds are shown on circuit diagram page.
02 - Symbols |
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NOTE: All switches shown in this manual are in "at rest" position.
NOTE: Additional information
CAUTION: Possible damage to vehicle or equipment
WARNING: Possible injury to mechanic
03 - Fuse / Power / Light data |
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Power Bus Information
The GENERATOR and BATTERY connect together at the JUNCTION BLOCK. The JUNCTION BLOCK is the Power Distribution point for car circuits.
The IGNITION SWITCH, LIGHT SWITCH, TAIL LIC RMRKR, BODY, STOP HAZ, CLK LTR ANT fuses and HORN circuit breaker are hot at all times, as well as some in-line fuses.
Fusible Links
A FUSIBLE LINK is a length of wire four (4) gauges smaller than the cable it protects. The FUSIBLE LINK insulation is different from other wires. In case of a short, the FUSIBLE LINK melts, opening the circuit to protect electrical components.
CAUTION: Replace fusible links with an exact replacement only. Make tight crimp joints and hot solder joints for good connections.
Self-Resetting Circuit Breakers
Some circuits are protected by self-resetting circuit breakers. Each circuit breaker has a set of contacts connected by a bi-metallic strip. If the strip becomes too hot (overcurrent), the bi-metallic strip bends out of shape, opening the circuit. When the bi-metallic strip cools down, the contacts are closed, and current flows through the circuit breaker again.
The circuit breaker cycles (opens and closes) as long as the overcurrent exists.
| Fuse Name | Amp Rating | Circuits protected |
| CRN PRK | 10 | Cornering, Front Marker, Park, Theft Deterrent, Trip Computer |
| CRUISE A/C | 15 | Automatic Climate Control; Cruise Control, Generator Charging Light, Diesel Engine Indicators, Trip Computer |
| B/U TRANS | 25 | Backup Lights, Diesel Engine: Automatic Climate Contril, Diesel Engine: Carge/Pre-Ignition, Downshift Solenoid, Ignition (ESS), Illuminated Entry, Sunroof |
| GAUGES | 5 | Warning Lights, Diesel Engine: Indicators, Delayed Pulse Wiper/Washer, Fuel Economy Indicators, Fuel Gauge, Seatbelt Chimes.Oil Pressure Indicator, Trip Computer |
| DIR SIG | 25 | Turn Lights, Electrical Leveling System |
| HORN CIRCUIT BREAKER | 40 | Automatic Door Locks, Horns, Power Seats, Power Door Locks, Power Seat Recliner, Stop: Engine Temperature Indicator, Trunk Pull Down |
| TAIL LICC RMRKR | 25 | Park, Marker, License, and Cornering Lights, Theft Deterrent, Trip Computer, Twilight Sentinel |
| INST LPS | 3 | Instrument Panel Illumination and Digital Displays |
| WDO CIRCUIT BREAKER | 40 | Power Windows, Trunk Release |
| WIPER | 25 | Delayed Pulse Wiper / Washer, Electronic Leveling Control, Theft Deterrent |
| RADIO | 7.5 | Radio / Power Antenna/Didital Clock |
| CLK LTR ANT | 20 | Power Antenna, Theft Deterrent, Ignition Key Warning, Courtesy and Glove Box Lights, Cigar Lighter; Trip Computer |
| STOP HAZ | 25 | Hazard / Stop Lights |
| BODY | 20 | Automatic Door Locks, Vanity, Courtesy, Reading, and Trunk Lights, Cigar Lighters, Electronic Leveling Control, Illuminated Entry, Belt Retractors, Power Door Locks, Power Mirrors, Theft Deterrent |
| Function | Bulb number | Candlepower |
| Ashtray Illumination | 1445 | .7 |
| Backup Light | 1156 | 32 |
| Brake Warning Indicator | 194 | 2 |
| ATC Illumination | 168 | 3 |
| Cornering Light | 1156 | 32 |
| Courtesy - Instrument Panel | 906 | 6 |
| Courtesy - Front Doors | 562 | 6 |
| Courtesy - Rear Doors | 562 | 6 |
| Cruise Control Indicators | 192 | 2 |
| Cruise Control Switch Light | 161 | 1 |
| Diesel Engine Start Indicator | 161 | 1 |
| Diesel Engine Wait Indicator | 161 | 1 |
| Door Lock Illumination | 558 | 2.5 |
| Dome Light | 562 | 6 |
| Engine Temperature Indicator | 194 | 2 |
| Fuel Economy Indicator | 74 | .75 |
| Fuel Gauge | 161 | 1 |
| Generator Indicator | 194 | 2 |
| Headlight - Inner | 4651 | 50W |
| Headlight - Outer | 4652 | 60W / 40W |
| Headlight Switch | 161 | 1 |
| High-Beam Indicator | 194 | 2 |
| Instrument Cluster | 194 | 2 |
| Instrument Panel Compartment | 1816 | 3 |
| License | 194 | 2 |
| License (Commercial) | 19467 | 4 |
| Lever Ride Indicator | 161 | 1 |
| Low Brake Warning Indicator | 194 | 2 |
| Oil Pressure Warning | 194 | 2 |
| Reading Light, Dome | 562 | 6 |
| Reading Light, Rear | 1004 | 15 |
| Turn / Park | 1157 | 32 / 3 |
| Radio Illumination | 1893 | 2 |
| Radio - Stereo w / Integral Tape Player Illumination | 563 | 4 |
| Trunk Compartment | 1003 | 15 |
| Rear Deck Lid Indicator | 161 | 1 |
| Rear Grid Defogger Indicator | 1445 | .7 |
| Seat Belt Indicator | 194 | 2 |
| Theft Deterrent Indicator | 194 | 2 |
| PRND21 Indicator | 161 | 1 |
| Front Marker Light | 194A | 2 |
| Rear Marker Light | 194 | 2 |
| Spot Light - Front Compartment | 1004 | 15 |
| Turn / Stop Light | 1157 | 32 / 3 |
| Turn Signal Indicator | 194 | 2 |
| Vanity Mirror | 562 | 6 |
| Windshield Washer Fluid Level | 161 | 1 |
| Windshield Wiper Switch Illumination | 161 | 1 |
| Washer Fluid Indicator | 161 | 1 |
| Water Temperature Warning | 194 | 2 |
| Thermometer Illumination | 194 | 2 |
| Dome Light | 562 | 6 |
| CB Radio Illumination | 1893 | 2 |
| AWG | METRIC |
| 0 | 50 |
| 2 | 32 |
| 8 | 8 |
| 10 | 5 |
| 12 | 3 |
| 14 | 2 |
| 16 | 1 |
| 18 | .80 |
| 20 | .50 |
| 24 | .22 |
04 - Power distribution |
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05 - Charge / Key warning buzzer / Stop: Engine temperature indicator |
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CIRCUIT OPERATION
Charge
With the IGNITION SWITCH in "Run", 12 volts is applied through the CRUISE A/C FUSE to the GENERATOR INDICATOR. If the engine is off en the GENERATOR is not working, current flows through the fuse, the indicator bulb, and the GENERATOR (to ground). The bulb goes on.
With the engine on, the GENERATOR powers all car electrical equipment and charges the BATTERY. Alternating current is generated by the stator as the field rotates. The rectifier bridges change the alternating current to direct current. When the GENERATOR is working, equal voltage is applied through the BRN wire to the other side of the indicator bulb. The light goes off.
The amount of DC voltage produced by the GENERATOR is controlled by the regulator. When the GENERATOR output voltage is low, the regulator increases current flowing through the field. This increases the GENERATOR'S output voltage (at terminal BAT). Field current is supplied directly from the stator's output through the diode trio.
Key Warning Buzzer
The KEY WARNING BUZZER sounds whenever the key is in the ignition switch and the left front door opens.
The closed IGNITION KEY SWITCH and LEFT FRONT DOOR SWITCH also provide a ground path (through the LT GRN wire) for the "Stop: Engine Temperature" INDICATOR, lighting the bulb as a test.
Engine Temperature Indicator
The "Stop: Engine Temperature INDICATOR lights:
1. if the driver's door opens and the key is in the IGNITION SWITCH (bulb test)
2. if the engine block temperature exceeds 320°F (160°C).
The closed ENGINE TEMPERATURE SWITCH also provides a ground path (through the LT GRN wire) for the KEY WARNING BUZZER. The buzzer sounds until temperature drops below 240°F (116°C).
TROUBLESHOOTING
Most Common Charge System Problems:
- Dead BATTERY
- BATTERY using too much water
- GENERATOR INDICATOR lit at normal speed
IMPROPER CHARGING
- Check generator belt tension.
- Check battery charge indicator.
- Check BATTERY if indicator is dark whether green dot is visible or not.
- Do not charge BATTERY if indicator is lit. Replace BATTERY.
- Check for tight, clean connections at GENERATOR and BATTERY.
NOTE: Read shop manual for detailed charging system tests.
"STOP: ENGINE TEMPERATURE" INDICATOR WON'T LIGHT
COMPONENT LOCATION
| Page/Figure | ||
| Diode Trio | Inside generator slip ring end frame | 5-2 |
| Engine Temperature Switch | Lower left rear side of engine (Diesel) | 34-1 |
| Key Warning Buzzer | Left side of dash | 19-1 |
| Rectifier Bridge | Inside generator slip ring end frame | 5-2 |
| Voltage Regulator | Inside generator slip ring end frame | 5-2 |
C101 |
Fuse block |
5-1 |
| C102, C102A | Steering column | 14-1 |
| C102B | Steering column | 14-1 |
| C103 | Bulkhead, behind fuse block | 5-1 |
| C103B | Bulkhead, engine harness | 5-1 |
| C116 | Under dash | 16-1 |
| C201A | Fuse block | 5-1 |
06 - Electronic fuel injection |
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CIRCUIT OPERATION
The EFI controls fuel injection and limits emissions by balancing the air/fuel mixture.
NOTE: The normal engine timing advance is 10° before TDC (8° in California).
Figure 6-1 shows inputs which govern the outputs of the Electronic Control Unit.
TROUBLESHOOTING
For detailed procedures, read "Electronic Fuel Injection" in 1979 Cadillac Service Manual.
COMPONENT LOCATION
| Page/Figure | ||
| Air Temperature Sensor | Rear engine | 36-1 |
| Coolant Temperature Sensor | Front left engine (Gasoline) Front engine (Diesel) |
36-1 34-1 |
| EGR Solenoids | Top engine, on throttle body assembly | 6-2 |
| Electronic Control Unit | Under dash, below radio | 6-3 |
| ESS Decoder | Left side of cowl, near junction block | 8-1 |
| Fast Idle Valve | Top of engine, on throttle body assembly | 6-2 |
| Fuel Pump (frame) | Frame, near left rear wheel | 6-4 |
| Fuel Pump (tank) | Fuel tank | 6-4 |
| In-Line Fuse | Wired in EFI manifold harnass, near ECU | |
| Junction Block | Left side of cowl | 8-1 |
| Speed Sensor | Part of distributor | 5-3 |
| Throttle Position Switch | Top of engine, throttle body assembly | 6-2 |
C101 |
Fuse block |
5-1 |
| C107 | EFI manifold harness, rear of engine | 36-1 |
| C129 | Under dash at ECU | 25-3 |
| C130 | Under dash at ECU | 6-3 |
| C131 | Under dash at ECU | 6-3 |
| C132 | Under dash at ECU | 6-3 |
| C157 | Rear of engine at air temperature sensor | 36-1 |
| C158 | Front of engine at coolant temperature sensor | 36-1 |
| C159 | At speed sensor | 5-3 |
| C167 | Under dash at ECU | 36-1 |
| C201 | Fuse block | 5-1 |
| C202 | Rear body harness | 14-2 |
| C202A | Rear body harness | 14-2 |
| C220 | Clipped to left rear of fuel tank | 6-4 |
| C223 | Above rear of fuel tank | 6-4 |
07 - Ignition (Gasoline engine) |
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CIRCUIT OPERATION
Distributor
With the IGNITION SWITCH in Start or Run, current flows to the DISTRIBUTOR through the PNK wire. As the engine turns, the TIMER CORE (figure 7-1) rotates. This makes and breaks a magnetic circuit each time a spark plug fires.
When the distributor shaft rotates, the CORE teeth come together with the POLE teeth, and magnetic flux flows from the PERMANENT MAGNET through the MAGNETIC PICKUP COIL and back to the PERMANENT MAGNET. As the rotating CORE teeth pass by the POLE teeth, the magnetic flux drops, causing a voltage signal in the MAGNETIC PICKUP COIL. This voltage is sensed and amplified by the HEI MODULE. The HEI MODULE switches a high current signal through the IGNITION COIL PRIMARY. The PRIMARY current creates magnetic energy, which is stored in the iron frame of the COIL.
As the CORE teeth come together with the POLE teeth again, the magnetic flux rises, and a different voltage signal (opposite polarity) is generated in the MAGNETIC PICKUP COIL. This signal causes the HEI MODULE to interrupt the PRIMARY current. This collapses the magnetic field in the COIL, generates a high voltage in the IGNITION COIL SECONDARY, and fires one spark plug.
NOTE: The transistorized HEI MODULE is a high-energy ignition unit which controls spark triggering, switching, current limiting (about 6 amps), dwell control (varied directly with RPM) and distributor pick-up.
CAUTION: Because of the high HEI voltage (35,000 volts), special 8mm diameter spark plug wires with silicone insulation are used. Silicone insulation is soft and must be handled with extreme care. Replace any scratched or nicked wire.
The RADIO NOISE CAPACITOR suppresses noise generated in the DISTRIBUTOR.
The SPEED SENSOR generates two electrical signals directly related to RPM. These signals are sent to the EFI ELECTRONIC CONTROL UNIT (1), synchronizing the INJECTOR GROUPS with the timing of the intake valves (phasing) and (2) scheduling fuel consumption.
Electronic Spark Selection (ESS)
The ESS system advances or retards the IGNITION, depending on various operating conditions. Fuel economy is improved at cruising speeds and exhaust emissions are reduced. Restarting of a hot engine is improved.
Figure 7-2 shows the different ESS operating modes.
There is no change in engine timing during normal city driving. When the engine is cold (below about 130°F or 54°C), California cars have retarded spark. (This decreases catalytic converter warm-up time and reduces emissions.) 49-States cars have normal spark advance during this operation. When starting engine, the spark is retarded from normal advance on all cars. (This improves hot starting because ignition occurs closer to the beginning of the power stroke.) Spark timing is advanced during driving conditions (improves fuel economy).
The RPM signal (ignition timing) is sent from the MAGNETIC PICKUP COIL to the ESS DECODER. The ESS DECODER output signal is sent on the BLK wire to new 5th pin (terminal D) on the HEI MODULE. This signal either delays or does not delay the interruption of PRIMARY current. The engine start signal is sent to the ESS DECODER (C128, terminal 2) on the DK GRN wire. Engine vacuum (detected by the FUEL ECONOMY VACUUM SWITCH) is sensed by the LT BLU wire at C128, terminal 4).
Engine coolant temperature is indirectly sensed by the ESS through the ELECTRONIC FUEL INJECTION ECU. The COOLANT TEMPERATURE SENSOR is connected to the ECU (see chapter 06 - Electronic Fuel Injection). When the engine is cold, the ECU energizes the EGR SOLENOID, and the exhaust gas recirculation is shut off. The ECU applies about +12 volts to the EGR SOLENOID. On California cars, +12 volts is applied to the ESS DECODER input (C128, terminal 1). On 49-State cars, the input to ESS DECODER is grounded. With the input at ground, the spark is set for normal advance. The DECODER senses this difference, and retards the spark on the cold engine California cars. When the engine warms, the ECU grounds and de-energizes the EGR SOLENOID through C131, terminal E (BLK wire to ENGINE GROUND), and the spark changes to normal advance.
Fuel Economy Indicators
When cruising, or with light throttle acceleration, the FUEL ECONOMY VACUUM SWITCH closes and the green indicator lights. With heavy acceleration the switch opens. The amber indicator lights (heavy fuel consumption). With the engine stopped, the amber indicator lights when the IGNITION SWITCH is turned to Start or Run.
Engine Coolant Temperature Switch
If the engine coolant temperature rises above 260°F (127°C), the ENGINE COOLANT TEMPERATURE SWITCH closes. The red indicator lights. As a bulb check, when the IGNITION SWITCH is turned to Start, current flows from the indicator light through the DIODE ASSEMBLY and to ground through the IGNITION SWITCH.
TROUBLESHOOTING
For detailed troubleshooting, read "ESS Service instructions" in 1979 Service Manual.
COOLANT TEMPERATURE INDICATOR WON'T LIGHT DURING START
- To check DIODE ASSEMBLY, connect lead across terminals DZ and FZ on C103B (short out DK GRN wires). Turn IGNITION SWITCH to Start and watch COOLANT TEMPERATURE INDICATOR.
AMBER FUEL ECONOMY INDICATOR WON'T LIGHT
- Connect lead from terminal EW (WHT wire) on C103B to ground. With engine off, turn IGNITION SWITCH to Start or Run and watch amber light.
COMPONENT LOCATION
| Page/Figure | ||
| Diode Assembly | Tapped to dash harness at fuse block | |
| EGR and Spark Solenoids | Top of engine assembly | 6-2 |
| Electronic Control Unit (ECU) | Under dash, below radio | 6-3 |
| Engine Coolant Temperature Switch | Top front of engine (Gasoline) Front engine (Diesel) |
36-1 34-1 |
| ESS Decoder | Left side of cowl, near junction block | 8-1 |
| Fuel Economy Switch | Mounted on center of cowl near windshield wiper/washer motor | |
| Speed Sensor | Part of distributor | 5-3 |
| C103 | Bulkhead, behind fuse block | 5-1 |
| C103B | Bulkhead, engine harness | 5-1 |
| C107 | EFI manifold harness, rear of engine | 36-1 |
| C127 | Center of cowl at ESS decoder | 8-1 |
| C128 | Center of cowl at ESS decoder | 8-1 |
| C130 | Under dash at ECU | 6-3 |
| C127 | Under dash at ECU | 6-3 |
| C127 | Under dash at ECU | 6-3 |
08 - Starter |
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CIRCUIT OPERATION
When the IGNITION SWITCH is turned to Start, current flows through the STARTER SOLENOID windings and the STARTER MOTOR. The motor begins to turn slowly, allowing the gear teeth to mesh. The MOTOR contacts close and BATTERY power bypasses the PULL-IN WINDING and flows directly to the STARTER MOTOR. Current flowing through the HOLD-IN WINDING keeps the STARTER SOLENOID engaged until the engine starts.
When the IGNITION SWITCH is released, current from the IGNITION SWITCH to the HOLD-IN WINDING is cut off. Current from the battery is sent in the reverse direction through the PULL-IN WINDING, but continues in normal direction through the HOLD-IN WINDING. The magnetic force of the HOLD-IN WINDING is canceled by the reverse force of the PULL-IN WINDING. The STARTER SOLENOID releases the DRIVE MECHANISM and opens the MOTOR CONTACTS. STARTER MOTOR current is interrupted.
COMPONENT LOCATION
| Page/Figure | ||
| C103 | Bulkhead, behind fuse block | 5-1 |
| C103B | Bulkhead, engine harness | 5-1 |
09 - Headlights |
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TROUBLESHOOTING
HEADLIGHT CIRCUIT BREAKER CYCLES
- If equipped with TWILIGHT SENTINEL, disconnect SENTINEL AMPLIFIER.
- Check for short in HEADLIGHTS.
GROUP OF LIGHTS IS OUT
- Check FRONT LIGHTS GROUND.
- Check connections at HEADLIGHT DIMMER SWITCH.
- Check for voltage at LIGHTS and HEADLIGHT DIMMER SWITCH.
COMPONENT LOCATION
| Page/Figure | ||
| Headlight Dimmer Switch | Left toe board | 10-1 |
| High Beam Indicator | Part of speedometer instrument panel | |
| Light Switch | Left side of instrument panel | 11-2 |
| C103 | Bulkhead, behind fuse block | 5-1 |
| C103B | Bulkhead, engine harness | 5-1 |
| C109 | Under left dash | 12-2 |
| C156 | Under left dash | 10-1 |
10 - Guidematic headlight control |
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CIRCUIT OPERATION
The GUIDEMATIC system automatically dims the hi beams when oncoming traffic is sensed.
The PHOTOCELL senses light from approaching headlights. PHOTOCELL sensitivity is adjusted by the DIMMER RHEOSTAT.
When the PHOTOCELL senses headlights, the AMPLIFIER sends a signal through the GRY wire, through the floor dimmer switch, and through the LT BLU and PPL wires to energize the DIMMER RELAY. The relay switches power to the lo beams.
When the PHOTOCELL senses darkness, the AMPLIFIER interrupts the signal to the DIMMER RELAY (DIMMER RELAY de-energized). The lights switch back to hi beam.
If the floor dimmer switch is slightly depressed, the OVERRIDE SWITCH closes. The amplifier is grounded through the DK GRN wires and the override switch. The high beams are turned on. The high beams can be flashed for signaling by rapidly closing and opening the OVERRIDE SWITCH.
TROUBLESHOOTING
NO HEADLIGHTS
- Check FRONT LIGHTS GROUND (Ground Page).
- Check input voltage to DIMMER RELAY (connector C112, terminal J, YEL wire).
- Check DIMMER RELAY output voltages (connector C112, terminals H and K, LT GRN and TAN wires).
GUIDEMATIC DOESN'T WORK
- Connect GUIDEMATIC PHOTOCELL/ AMPLIFIER terminal D to ground and operate GUIDEMATIC.
- Check AMPLIFIER input voltages (terminals A and C, LT BLU and DK GRN wires).
- Check AMPLIFIER output voltage (terminal B, GRY wire).
COMPONENT LOCATION
| Page/Figure | ||
| Dimmer Relay | Mounted on left side of cowl | 10-3 |
| Dimmer Rheostat | Part of headlight switch | 11-1 |
| Guidematic Photocell / Amplifier | Begind the front grille | 10-2 |
| Headlight Dimmer Switch | Left toe board | 10-1 |
| C103 | Bulkhead, behind fuse block | 5-1 |
| C103A | Bulkhead, front light harness | 5-1 |
| C109 | Dash harness, near light switch | 12-2 |
| C112 | Under left dash | 10-1 |
| C123 | Under left dash | 10-1 |
| C154 | Behind front grille | 10-2 |
| C155 | Dash harness, near light switch | 11-1 |
11 - Twilight sentinel |
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CIRCUIT OPERATION
The TWILIGHT SENTINEL automatically turns the headlights and exterior lights on at dusk, and off at dawn. It also keeps the headlights on for up to 4½ minutes after leaving the car.
Twilight Sentinel
With the IGNITION SWITCH in Run, the AMPLIFIER is activated by switching the control On (AMPLIFIER grounded). The PHOTOCELL senses darkness. When resistance through the PHOTOCELL reaches a pre-set value (threshold), the AMPLIFIER switches, sending current from terminal K to terminals F and H, powering the headlights and exterior lights.
NOTE: The AMPLIFIER will not respond to resistance changes in the PHOTOCELL for about 30 seconds. This keeps the SENTINEL from activating under street lights or in tunnels.
Delayed Exit
With the IGNITION SWITCH in Off or Lock, the SENTINEL CONTROL can be set to leave the headlights and exterior lights on for up to 4½ minutes. A variable timer in the AMPLIFIER automatically shuts off the lights after time expires.
TROUBLESHOOTING
TWILIGHT SENTINEL DOESN'T WORK
- Turn on PARKING LIGHTS to check fuse.
- Check AMPLIFIER ground connection through SENTINEL CONTROL SWITCH (terminal L) and LIGHT SWITCH (terminal B).
- Check voltage at AMPLIFIER.
- Check PHOTOCELL resistance.
- Check SENTINEL CONTROL resistance.
- Check AMPLIFIER output voltages (terminals F and H).
COMPONENT LOCATION
| Page/Figure | ||
| Photocell | Under left front speaker grille | 11-2 |
| Sentinel Amplifier | Behind left dash | 11-2 |
| Sentinel Control | Part of light switch | 11-1 |
C109 |
Dash harness, near light switch |
11-2 |
C118 |
Behind left dash |
11-2 |
C150 |
Left side of dash, near light switch |
11-2 |
12 - Front park / Marker / Cornering lights |
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CIRCUIT OPERATION
With the LIGHT SWITCH pulled out to the first or second detent, current flows through the CRN PRK fuse to operate the PARK, MARKER, and CORNERING LIGHTS. All these lights are wired in parallel.
TROUBLESHOOTING
GROUP OF LIGHTS OUT
- Watch ASH TRAY ILLUMINATION to check fuse.
- Check for voltage at BULKHEAD CONNECTOR (C103A, terminal CT).
- Check for voltage at C105/C106, terminal B.
- Check for open ground (Ground Page).
SINGLE LIGHT OUT
- Check light socket connections.
- Check for open ground.
- Check for broken wire.
COMPONENT LOCATION
| Page/Figure | ||
| C102 | Base of steering column | 14-1 |
| C102A | Base of steering column | 14-1 |
| C103 | Behind fuse block | 12-1 |
| C103A | LH side of firewall | 12-1 |
| C105 | LH front fender | 12-1 |
| C106 | RH front fender | 12-4 |
| C109 | Dash harness, near light switch | 12-2 |
| C111 | Dash harness, near ash tray | 17-2 |
| C168 | Dash harness, near radio | 17-2 |
| Front Light Grounds | RH side of radiator support | 12-4 |
13 - Rear park / Marker / License / Backup lights |
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TROUBLESHOOTING
GROUP OF LIGHTS OUT
- Check voltage at CRN PRK FUSE (RH terminal).
- Check rear body ground or LICENSE PLATE ground.
- Check for circuit continuity.
SINGLE LIGHT OUT
- Check bulb.
- Check bulb socket connection.
BACKUP LIGHTS DON'T WORK
- Operate ILLUMINATED ENTRY or SUNROOF to check fuse.
- Jiggle gear selector lever to check the backup switch linkage.
- Check power and ground connections at BACKUP SWITCH. Check for voltage at BACKUP SWITCH.
COMPONENT LOCATION
| Page/Figure | ||
| Backup Light Switch | Base of steering column | 14-1 |
| Opera Lights | Upper quarter panels | |
C101 |
Fuse block |
13-1 |
| C103 | Bulkhead | 5-1 |
| C109 | Under left dash | 12-2 |
| C201 | Fuse block | 13-1 |
| C202 | At left trunk hinge | 13-2 |
| C202B | At left trunk hinge | 13-2 |
| C215 | At left trunk hinge | 13-2 |
| C288 | Near left trunk hinge | 13-2 |
14 - Turn / Hazard / Stop lights |
Back to the top |
TROUBLESHOOTING
NO TURN SIGNALS
- Check DIR SIG FUSE.
- Check connections at flasher socket.
- Check connection of TURN SIGNAL CONNECTOR, C102, and FUSE PANEL CONNECTOR C101.
- Replace TURN SIGNAL FLASHER.
NO RIGHT FRONT TURN SIGNALS
- Check voltage at TURN LIGHT (C 106, terminal A, LT BLU wire).
- Connect TURN LIGHT (BLK wire) to ground and observe lights (see front light ground, Ground Page).
- Change both right front turn signal bulbs.
TURN SIGNALS FLASH ON ONE SIDE ONLY
- Check for burned-out bulbs.
- Check continuity through switch.
- Check continuity through turn/hazard switch.
- Check for bad ground.
NO HAZARD LIGHTS
- Operate STOP LIGHTS to check STOP HAZ FUSE.
- Check HAZARD FLASHER connections.
- Replace HAZARD FLASHER.
NO STOP LIGHTS
- Operate HAZARD FLASHER to check the STOP/HAZ FUSE.
- Check for continuity through STOP LIGHT SWITCH.
- Check voltage to STOPLIGHTS at TURN SIGNAL connector (C101, terminals B and E, YEL and DK GRN wires, D and E, YEL and DK GRN wires).
COMPONENT LOCATION
| Page/Figure | ||
| Stoplight Switch | Brake pedal support | 14-2 |
| Turn Signal Flasher | Dash harness near LH side panel | 14-2 |
C101 |
Fuse block |
5-1 |
| C102 | Steering column | 14-1 |
| C102B | Steering column | 14-1 |
| C103 | Bulkhead, behind fuse block | 5-1 |
| C103A | Bulkhead, front lights harness | 5-1 |
| C105 | Front left fender | 12-1 |
| C106 | Front right fender | 12-4 |
| C201 | Fuse block | 5-1 |
| C202 | Rear body harness | 13-2 |
| C202A | Rear body harness | 13-2 |
15 - Courtesy / Reading / Trunk / Glove box lights / Cigar lighter / Illuminated entry |
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CIRCUIT OPERATION
Illuminated Entry
The ILLUMINATED ENTRY TIMER is powered through the BODY FUSE when either FRONT DOOR LOCK CYLINDER SWITCH closes. All of the inside courtesy lights turn on and automatically turn off after about 20 seconds. The outside DOOR LOCK CYLINDERS are also illuminated by a fiber optic circuit routed from the front door courtesy light. If the IGNITION SWITCH is turned on before the 20 second period elapses, voltage is applied through the B/U TRANS FUSE to the ILLUMINATED ENTRY TIMER and the TIMER re-sets. The COURTESY LIGHTS turn off immediately.
TROUBLESHOOTING
ILLUMINATED ENTRY DOESN'T WORK
- Operate BACKUP LIGHTS to check B/U TRANS FUSE.
- Operate COURTESY LIGHTS to cheek BODY FUSE.
- Check ILLUMINATED ENTRY TIMER connections. Check voltage at ILLUMINATED ENTRY TIMER.
GROUP OF COURTESY LIGHTS DOESN'T WORK
- Operate REAR DOOR CIGAR LIGHTERS to check BODY FUSE.
- Check voltage at FUSE BLOCK CONNECTOR C201A (terminal L).
- Check voltages at BODY CONNECTORS C212 and C213 (ORN wires).
- Connect BODY CONNECTORS C212 and C213 (WHT wires) to ground and observe COURTESY LIGHTS.
COMPONENT LOCATION
| Page/Figure | ||
| Illuminated Entry Timer | On cowl above fuse block | |
| Illuminated Lock Cylinder Switches | Front doors | |
| Left Reading Light Ground | Left rear upper quarter panel | 15-1 |
| Right Reading Light Ground | Right rear upper quarter panel | 15-1 |
C101 |
Fuse block |
5-1 |
| C109 | Dash harness, near light switch | 12-2 |
| C110 | Dash harness, near radio | 17-2 |
| C111 | Dash harness, near ash tray | 17-2 |
| C170 | At left front doorlock cylinder | 15-2 |
| C171 | At left front doorlock cylinder | 15-2 |
| C178 | Seatbelt retractor harness, at console | 15-3 |
| C201A | Fuse panel | 18-1 |
| C201 | Fuse block | 5-1 |
| C201A | Crossbody harness at fuse block | 5-1 |
| C202 | Front body harness, at left trunk hinge | 13-2 |
| C202B | Rear body harness, at left trunk hinge | 13-2 |
| C202C | At left trunk hinge | 13-2 |
| C208 | Left front door and seat harness, at "B" pillar | 20-2 |
| C208A | Left read door harness, at "B" pillar | |
| C208B | Dome and reading light harness, at "B" pillar | |
| C211 | Right front door and seat harness, at "B" pillar | 20-1 |
| C211A | Right read door harness, at "B" pillar | |
| C211B | Seatbelt retractor harness, at right "B" pillar | |
| C212 | At left "A" pillar | 20-2 |
| C212A | Left front door and seat harness, at left "A" pillar | 20-2 |
| C212B | Illuminated entry cross body harness | |
| C213 | At right "A" pillar | 20-1 |
| C213A | Right front door and seat harness at right "A" pillar | 20-1 |
| C213B | Automatic door lock harness at right "A" pillar | 20-1 |
16 - Rear grid defogger |
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CIRCUIT OPERATION
When the REAR DEFOG SWITCH is pressed On (momentary), current passes through the LT GRN wire and energizes the relay coil. Current flows through the YEL wire, through tile closed contact of the relay, through the TIMER to ground (keeps the relay energized), and to the grid defogger. The indicator lights.
As soon as current flows through the TIMER, it begins a countdown (about 20 minutes). After about 20 minutes, the TIMER interrupts current to the relay coil, opening the relay contact and cutting off power to the grid defogger. The indicator light goes out.
If the DEFOG SWITCH is pressed to Off (momentary), the relay coil is grounded through the LT GRN wire. The relay coil is de-energized and power to the GRID DEFOGGER is cut off.
TROUBLESHOOTING
HEATER DOESN'T WORK
- Check circuit breaker connections. Check continuity through circuit breaker.
- Check switching of voltage to TIMER at C117 (LT GRN wire) when switch is pressed On and Off (TIMER input).
- Check switching of voltage at TIMER output (terminal L or C117, PPL wire).
INDICATOR LIGHT IS ON BUT NOT HEATER
- Check for voltage at GRID DEFOGGER connector (PPL wire).
HEATER GRID LINES OPEN
- Perform grid line tests per Cadillac Service Manual.
COMPONENT LOCATION
| Page/Figure | ||
| Rear Defog Circuit Breaker | Mounted on dash bracket, under steering column | 16-1 |
| Time Delay Relay | Left rear quarter panel in trunk | 16-2 |
C113 |
Under center of dash |
16-1 |
| C117 | Behind left side of dash near fuse panel | 16-1 |
17 - Instrument panel illumination |
Back to the top |
TROUBLESHOOTING
GROUP OF LIGHTS IS OUT
- Operate REAR PARK MARKER and LICENSE LIGHTS to check TAIL LIC RMRKR FUSE.
- Check voltage at LIGHT SWITCH connector (C109, terminal D, GRN wire).
- Check for open ground.
SINGLE LIGHT IS OUT
- Check bulb.
- Check bulb socket for broken wires and loose connections.
COMPONENT LOCATION
| Page/Figure | ||
| C108 | Center dash harness | 17-2 |
| C109 | Dash harness, near headlight switch | 12-2 |
| C110 | Center dash harness | 17-2 |
| C113 | Under center of dash | 16-2 |
| C116 | Left side of dash near fuse block | 24-2 |
| C152 | Behind left dash panel | 19-1 |
18 - Brake and trunk warning / Vanity lights / Trunk release |
Back to the top |
TROUBLESHOOTING
BRAKE WARNING LIGHT STAYS ON
- Check PARKING BRAKE is released.
WARNING: If car must be moved, drive with extreme caution, or tow. Do not drive long distances without having system repaired.
VANITY MIRROR LIGHT DOESN'T WORK
- Check for voltage at C213 (ORN wire) by opening any door and observing COURTESY LIGHTS.
- Check VANITY MIRROR SWITCH.
REMOTE CONTROL TRUNK LOCK DOESN'T WORK
- With the IGNITION SWITCH in RUN, operate the POWER WINDOWS to check circuit braker.
- Check the TRUNK RELEASE SWITCH.
- Check voltage at the TRUNK LOCK SOLENOID (connector C216 BLK wire).
COMPONENT LOCATION
| Page/Figure | ||
| Brake System Switch | Brake combination valve mounted on left frame | |
| Trunk Lock Solenoid | Trunk Striker Plate | |
| Trunk Open Switch | Center of trunk lid | |
C101 |
Fuse block |
5-1 |
| C103 | Bulkhead, behind fuse block | 5-1 |
| C103A | Bulkhead, front lights harness | 5-1 |
| C114 | Dash harness near fuse block | 5-1 |
| C136 | Dash harness fuse block | 18-1, 18-3 |
| C201 | Fuse block | 5-1 |
| C205 | Cross body harness | 18-2 |
| C212 | Left side body harness | 18-2 |
| C213 | Right side body harness | 20-2 |
| C214 | Dash harness near fuse block | 5-1 |
| C216 | Trunk lock solenoid |
19 - Delayed pulse wiper / Washer |
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CIRCUIT OPERATION
Wiper Operation
With the IGNITION SWITCH in Acc or Run, voltage is applied through the WIPER FUSE to the WIPER RELAY Coil. When the WIPER/WASHER CONTROL is turned to either Lo, Med, or Hi, the GEARBOX RELAY contacts close, and voltage is applied to the PULSE RELAY. The PULSE RELAY contacts close, and current flows through the WIPER MOTOR. The WIPER operates at the selected speed.
For Lo speed, the WIPER/WASHER CONTROL switches 0 ohms in series with the shunt field of the WIPER MOTOR.
For Med speed, the 13 ohm resistor is switched in parallel with 20 ohms, providing slightly less than 8 ohms in series with the shunt field. More current is forced through the series winding. The WIPER MOTOR speed increases.
For Hi speed, the 20 ohm resistor is connected with the shunt field, and more current is forced through the series winding. The motor runs at the highest speed.
To turn the wiper off, the WIPER/ WASHER CONTROL is turned Off. Current through the GEARBOX RELAY coil is interrupted, but the contacts remain closed. The WIPER MOTOR continues to run. When the wipers reach Park position, the GEARBOX RELAY contacts are mechanically opened by the cam. Current to the PULSE RELAY and the WIPER MOTOR is then interrupted.
Pulse Operation
For controlled Delay between wiper sweeps, the WIPER/WASHER CONTROL is switched down and to the right. Current is sent to the PULSE WIPER TIMER through the DELAY RHEOSTAT. By adjusting the RHEOSTAT, the time between sweeps can be varied from 0 seconds up to Max of about 12 seconds.
The GEARBOX RELAY is energized, sending current to the PULSE RELAY. When the set time is up, the PULSE WIPE TIMER switches the PULSE RELAY to ground, closing the contacts. The wiper sweeps once. The HOLDING SWITCH closes, resetting the TIMER. At the end of the wiper sweep, the HOLDING SWITCH opens, and the timer begins to time out again.
The delayed wipe is turned Off by turning the WIPER/WASHER CONTROL Off. Current to the GEARBOX RELAY is interrupted. The WIPER completes one final sweep. At the end of the sweep, the HOLDING SWITCH opens, interrupting current to the PULSE RELAY.
Washer Operation
The WINDSHIELD WASHER is turned on by depressing the WASH SWITCH. Current is sent to the WASHER OVERRIDE SWITCH, the GEARBOX RELAY, and the PULSE RELAY. The washer squirts about 8 times while the wipers sweep about 4 times in Lo speed. After the washer completes the squirts, the wipers sweep 2 additional times and automatically turn off.
If the WIPER/WASHER CONTROL is turned on to Lo, Med, or Hi when the WASH SWITCH is pressed, the WASHER operates as usual but the wipers run at the set speed. If the WIPER/WASHER CONTROL is switched to controlled Delay, pressing the WASH SWITCH closes the WASHER OVERRIDE SWITCH. This causes override of the delayed cycle. Following completion of the wash, the delayed cycle is resumed.
TROUBLESHOOTING
WIPER DOESN'T WORK
- Check WIPER FUSE.
- Check for power at WINDSHIELD PULSE WIPER and WASHER UNIT between terminals 2 and 3 of the 3-terminal connector (WIPER/WASHER CONTROL in Lo).
- Ground the GRY wire at WIPER WASHER CONTROL (terminal J). If wiper works, check switch; if not, check WINDSHIELD PULSE WIPE and WASHER unit.
CONTROLLED DELAY DOESN'T WORK
- Check DELAY RHEOSTAT.
WASHER DOESN'T WORK
- Ground the PNK wire at WIPER/WASHER CONTROL (terminal G). If washer works, check switch; if not, check WINDSHIELD PULSE WIPE and WASHER unit.
COMPONENT LOCATION
| Page/Figure | ||
| Washer Fluid Level Switch | Left fender inside washer fluid bottle | |
| Windshield Pulse Wiper and Washer | Mounted on cowl behind engine | |
C103 |
Bulkhead, behind fuse block |
5-1 |
| C103A | Bulkhead, front lights harness | 5-1 |
| C152 | Behind left dash panel | 19-1 |
20 - Power windows |
Back to the top |
CIRCUIT OPERATION
With the INGNITION SWITCH in "Run", voltage is applied through the WDO CIRCUIT BREAKER and the PNK wire to the DRIVER'S MASTER CONTROL and the passenger's window switches. When the driver's left front window switch is in "Up", current flows through the circuit breaker, switch terminals E and I, and the LH WINDOW MOTOR (to ground). The motor runs. The window goes up. Simmilar current flow will take place with the driver's RH window switch or each passenger's wwindow switch in "Up".
In "Dn", the motor runs in the opposite direction.
Note that current through the PNK wires to any of the passenger's window switches must pass through the WINDOW LOCK SWITCH. This can be used to break current flow to the passenger's window switches and stop all three motors that receive current through that lock switch.
TROUBLESHOOTING
NO WINDOWS WORK
- Operate TRUNK RELEASE to check WDO CIRCUIT BREAKER.
- Check WDO CIRCUIT BREAKER.
- Check voltage at DRIVER'S MASTER CONTROL (terminal E, PNK wire).
- Push left front toggle to Dn. Check voltage at DRIVER'S MASTER CONTROL (terminal H, BRN wire).
ONE WINDOW DOESN'T WORK
- Check continuity through WINDOW LOCK SWITCH.
- Check voltage and ground connections at WINDOW MOTOR.
COMPONENT LOCATION
| Page/Figure | ||
| C114 | Dash harness near fuse block | 5-1 |
| C203 | Cross body harness | 20-2 |
| C204 | Cross body harness | 20-1 |
| C205 | Cross body harness | 20-2 |
| C209 | Right front door and seat harness | 20-1 |
| C210 | Left front door and seat harness | 20-2 |
| C214 | Cross body harness, near fuse block | 5-1 |
| C217 | In door | |
| C269 | In door |
21 - Power seats (6 way) |
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CIRCUIT OPERATION
The drive unit in the SIX-WAY POWER SEATS is an electric motor controlled by a transmission. Three solenoids inside the transmission operate clutches to drive the seat fwd/back, front up/dn, or rear up/dn.
The numbers on the diagram above the POWER SEAT CONTROL match the numbers inside the CONTROL. These numbers show what switch closes when the POWER SEAT CONTROL is moved in each direction. For example: closing switch 3 (entire seat up) allows current flow from the circuit breaker through sections A and E (UP side). Current flows out of the SEAT CONTROL at terminal F, energizing the POWER SEAT RELAY coil (through terminal B), and through the DK BLU wire energizing the BACK/UP winding of the MOTOR, and on to ground. The RELAY coil is grounded at the same time through the WHT wire and FWD/DN winding of the MOTOR. Switch 3 also closes sections B and F, energizing the FRONT and REAR HEIGHT SOLENOIDS to drive the entire seat up.
TROUBLESHOOTING
NO SEAT CONTROLS WORK
- Sound HORNS to check circuit breaker.
- Check voltage at POWER SEAT SWITCH (terminal E, ORN/BLK wire).
- Push control toggle to Fwd. Check for voltage at POWER SEAT SWITCH (terminals D and B).
- Connect POWER SEAT RELAY (terminal B), to ground. Check for operation of POWER SEAT MOTOR.
- Check POWER SEAT SOLENOID grounds.
COMPONENT LOCATION
| Page/Figure | ||
| Power Seat Motor | Under front seat | 21-1 |
| Power Seat Relay | On power seat motor | 21-1 |
C114 |
Dash harness near fuse block |
21-3 |
| C173 | Under front seat, at power seat relay | |
| C174 | Under front seat, at power seat relay | |
| C205 | Cross body harness | 20-2 |
| C207 | Front seat harness | 21-1 |
| C214 | Dash harness near fuse block | 21-3 |
22 - Power seats (2 way) / Power door locks |
Back to the top |
CIRCUIT OPERATION
Two-Way Seat
The POWER SEAT MOTOR has two windings.
Current flows through one winding to move the seat forward, and the other winding to move the seat back.
The two-way switch sends current to the FWD or BACK winding.
Power Door Locks
When either door lock switch is pressed to Lock, current flows through the DK GRN/YEL wire to the DOOR LOCK RELAY. When the LOCK RELAY is energized, current flows from the ORN/BLK wire, through the relay contacts, through the GRY wire, through the lock motors, through the TAN wire, and to ground through the UNLOCK side of the DOOR LOCK RELAY.
NOTE: Current flows through the motor in one direction to lock, and the opposite direction to unlock.
In the "at rest" position, the LOCK and UNLOCK contacts of the relay are both grounded.
TROUBLESHOOTING
SEAT DOES NOT WORK
- Operate HORN to check circuit breaker.
- Check connections at the TWO-WAY SEAT SW1TCH.
- Check voltage at the TWO-WAY SEAT SWITCH (terminal 1, ORN/BLK wire).
- Check POWER SEAT MOTOR ground.
- Check input voltages to POWER SEAT MOTOR (DK GRN or YEL wire).
NO LOCKS WORK
- Sound the HORN to check circuit breaker. Open doors and observe COURTESY LIGHTS to check fuses.
- Check connections to POWER LOCK RELAY.
ONE LOCK DOES NOT WORK
- Check continuity of faulty lock motor circuit.
COMPONENT LOCATION
| Page/Figure | ||
| Door Lock Motor | In doors | 20-2 |
| Door Lock Relay | Base of right "A" pillar | 22-1 |
C101 |
Dash harness near fuse block |
5-1 |
| C114 | Dash harness near fuse block | 5-1 |
| C201A | Fuse block | 5-1 |
| C205 | Cross body harness | 20-2 |
| C206 | Cross body harness | 20-1 |
| C209 | Right front door harness | 20-1 |
| C210 | Left front door harness | 20-2 |
| C212 | Left side body harness | 20-2 |
| C212A | Left front door harness | 20-2 |
| C212B | Left front door harness | |
| C213 | Right side body harness | 20-1 |
| C214 | Dash harness near fuse block | 5-1 |
23 - Theft deterrent |
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CIRCUIT OPERATION
Arming the Security System
The SECURITY SYSTEM is armed by pressing a DOOR LOCK SWITCH to Lock. BATTERY voltage from the BODY FUSE is connected through the DOOR LOCK SWITCH to the ELECTRONIC CONTROLLER and enables the THEFT DETERRENT. The flashing signal from the ELECTRONIC CONTROLLER stops, and the INDICATOR glows continuously. When all the doors are closed, the DOOR JAMB SWITCHES are open and current to the INDICATOR is cut off. The SECURITY SYSTEM is armed.
Setting Off the Alarm
The SECURITY ALARM is set off when the DOOR LOCK CYLINDERS or the TRUNK LOCK CYLINDER is tampered with. Forcing the hood to the "Safety" position also sets off the alarm.
Tampering with any door lock cylinder, the trunk lock cylinder, or hood causes a TAMPER SWITCH to close. (The TRUNK can be opened with the key without closing the TAMPER SWITCH.) This grounds the ELECTRONIC CONTROLLER and activates the alarm signals. Current through one IN-LINE FUSE is pulsed to the horns by the ELECTRONIC CONTROLLER. Current through the other IN-LINE FUSE is pulsed to the LOW BEAM HEADLIGHTS and the PARKING, MARKER, TAIL, and LICENSE LIGHTS. The horns and lights are actuated at about 50 pulses per minute.
The alarm operates for 3 to 7 minutes. After shutting off, the SECURITY SYSTEM is automatically re-armed, unless a lock is damaged.
Disarming the Security System
Unlocking the door with a key disarms the system. The DISABLE SWITCH is closed, grounding the ELECTRONIC CONTROLLER. The CONTROLLER is reset, disabling the SECURITY SYSTEM. Turning the IGNITION SWITCH On connects battery voltage to the CONTROLLER through the WIPER FUSE. This also disarms the SECURITY SYSTEM.
When the alarm is set off, it can only be shut off by unlocking the door with the key. The DISABLE SWITCH closes, grounding the ELECTRONIC CONTROLLER. The CONTROLLER re-sets, and the alarm shuts off.
If a lock is damaged, the TAMPER SWITCH closes. With the IGNITION SWITCH Off, the ELECTRONIC CONTROLLER flashes the INDICATOR, warning the SECURITY SYSTEM is activated. With the IGNITION SWITCH to Acc or Run, the CONTROLLER turns the INDICATOR off. With the IGNITION Off, the INDICATOR continues to flash.
TROUBLESHOOTING
SECURITY SYSTEM INDICATOR FLASHES CONTINUALLY WITH IGNITION OFF (LIGHT GOES OUT WITH IGNITION ON)
- Inspect car for theft and lock damage.
- Check for faulty TAMPER SWITCH (failed closed).
- Repair or replace damaged switch.
SECURITY SYSTEM WILL NOT ARM
- Operate POWER DOOR LOCKS to check DOOR LOCK SWITCHES.
- Test for operation of COURTESY LIGHTS and CIGAR LIGHTERS to check BODY FUSE.
COMPONENT LOCATION
| Page/Figure | ||
| Diode Assembly | Taped to instrument panel harness, near C124 | |
| Electronic Controller | Behind instrument panel, to right of glove box | |
| In-Line Fuses | Wired in instrument panel harness, above glove box liner | |
C101 |
Fuse block |
5-1 |
| C103 | Bulkhead, behind fuse block | 5-1 |
| C103A | Bulkhead, front lights harness | 5-1 |
| C120 | Right upper dash | |
| C121 | Right upper dash | |
| C124 | Under left side of dash | |
| C201A | Fuse block | 5-1 |
| C212 | Cross body harness at "A" pillar | 18-2 |
| C212A | left side body harness | 20-2 |
| C212B | Left side body harness | 20-2 |
| C213 | Cross body harness | 20-1 |
| C224 | Door locks and theft deterrent harness under left side of dash | |
| C225 | Cross harness at left "A" pillar | 23-1 |
| C226 | Left door lock cylinder | 23-1 |
| C227 | Cross harness at right "A" pillar | 23-1 |
| C228 | Right door lock cylinder | 23-1 |
| C229 | Door locks and theft deterrent harness at left "A" pillar | |
| C230 | Door locks and theft deterrent harness at right "A" pillar | 20-1 |
| C231 | Trunk lid theft deterrent harness at left | |
| C232 | Trunk lid near lock cylinder |
24 - Cruise control |
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CIRCUIT OPERATION
NOTE: CRUISE CONTROL operates only when car is going 30 mph or faster.
Cruise Mode
With the CRUISE CONTROL SWITCH in Cruise, current flows to the CRUISE CONTROLLER through the LT BLU/BLK wire. The amber "CRUISE CONTROL ON" INDICATOR lights. Current flows through the CRUISE CONTROL BRAKE SWITCH, through the YEL wire to terminal F of the CRUISE CONTROLLER and terminal 1 of the BUTTON and SLIDE SWITCHES, and on to terminal E of the CRUISE CONTROLLER The cruise speed is ready to be set.
Cruise speed is set by interrupting current to terminal E of the CRUISE CONTROLLER (momentarily opening LOCK-IN BUTTON). When the cruise speed is set, the green "AUTO/CRUISE ON" INDICATOR lights. The SPEED SENSOR sends signals to the CONTROLLER telling car speed. The CONTROLLER then matches the car speed to the set cruise speed The throttle position is varied through the electrical and vacuum connections.
The cruise speed is reduced by holding the LOCK-IN BUTTON depressed. Car speed slows as long as the BUTTON is held in. Releasing the LOCK-IN BUTTON sets a new cruise speed.
The CRUISE CONTROL shuts off and cruise speed is canceled:
1. if the brake pedal is depressed;
2. if the CRUISE CONTROL SWITCH is turned Off;
3. if the IGNITION SWITCH is turned Off;
4. if the car speed falls below approximately 30 mph.
Auto Mode
With the CRUISE CONTROL switch in Auto, current flows to the CRUISE CONTROLLER through the LT BLU/BLK wire. The amber "CRUISE CONTROL ON" INDICATOR lights. Current flows through the CRUISE CONTROL BRAKE SWITCH, through the DK GRN wire, and to the CRUISE CONTROLLER terminals E (through the RED wire) and F (through the YEL wire). The auto/cruise speed is ready to be set.
Auto/cruise speed is set by interrupting current to terminal E of the CRUISE CONTROLLER (momentarily opening the LOCK-IN BUTTON). When auto/cruise speed is set, the green "AUTO/CRUISE ON" INDICATOR lights. The speed sensor sends signals to the CONTROLLER telling car speed. The CONTROLLER then matches the car speed to the set cruise speed. The throttle position is varied through the electrical and vacuum connections.
The cruise speed is increased by holding the SLIDE SWITCH depressed. Car speed increases at a gradual rate until the SLIDE SWITCH is released. Releasing the SLIDE SWITCH sets a new cruise speed.
Depressing the brake pedal does not cancel the cruise speed in Auto Mode. When car speed drops below 30 mph, the "AUTO/ CRUISE ON" INDICATOR goes out, but the memory stores the cruise speed. When the car speed goes above 30 mph, the SLIDE SWITCH can be momentarily depressed, and the Auto Mode re-activated. The "AUTO/CRUISE ON" INDICATOR lights, and car speed gradually increases up to the pre-set cruise speed.
The AUTO CRUISE CONTROL shuts off, and cruise speed memory is cancelled:
1. if the CRUISE CONTROL SWITCH IS turned Off;
2. if the IGNITION SWITCH is turned Off.
TROUBLESHOOTING
SPEED CONTROL DOESN'T WORK
- Operate AIR CONDITIONER to check A/C CRUISE FUSE.
- Check for input voltages at CRUISE CONTROLLER, terminals G, E, and F.
- Check for output voltages at CRUISE CONTROLLER, terminals C and H.
- Check vacuum and throttle cruise control linkage.
COMPONENT LOCATION
| Page/Figure | ||
| Cruise controller | Under dash | 24-1 |
| Power Unit Solenoid Valve | Top front engine | 34-1 |
| Speed Sensor | Under dash | 24-2 |
| Vacuum Control Valve | Center firewall | 34-1 |
C103 |
Bulkhead, behind fuse block |
5-1 |
| C103B | Bulkhead, engine harness | 5-1 |
| C116 | Under left side of dash, near fuse block | 24-2 |
| C135 | Cruise control harness | 24-2 |
| C166 | Under left side of dash | 36-1 |
25 - Electronic leveling control |
Back to the top |
CIRCUIT OPERATION
The HEIGHT SENSOR is connected to the rear axle by an actuating arm. The sensor detects the difference between what the height should be (pre-set value) and what the height is.
If the SENSOR detects more weight has been added (car too low), after a delay of about 12 seconds it grounds the ELC RELAY. Current flows through the closed contact of the ELC RELAY, powering the compressor and indicator light.
If the SENSOR detects weight has been removed (car too high), it grounds the vent solenoid. Current flows through the vent solenoid to ground, and the pneumatic system is vented.
When the height reaches the pre-set value, the SENSOR opens the ground circuits.
TROUBLESHOOTING
ELC WILL NOT WORK
- Check for voltage at ELC RELAY.
- Check for voltage at HEIGHT SENSOR (terminals 5 and 6, LT GRN and DK BLU wires).
- Check for voltage at COMPRESSOR MOTOR (DK GRN wire) or EXHAUST SOLENOID (DK BLU wire).
- Check for continuity to ground at HEIGHT SENSOR (terminals 2 and 3, YEL and WHT wires).
COMPONENT LOCATION
| Page/Figure | ||
| Compressor Motor | Left front fenderwell (part of ELC compressor assembly) | 25-1 |
| ELC Relay | Dash harness, near steering column | 25-3 |
| Height Sensor | Rear frame cross member | 25-2 |
| Vent Solenoid | Left front fenderwell (part of ELC compressor assembly) | 25-1 |
C101 |
Fuse block |
5-1 |
| C103 | Bulkhead behind fuse block | 5-1 |
| C103A | Bulkhead (connects to forward light harness) | 5-1 |
| C104 | Left engine compartment, near wheel well | |
| C175 | Near A/C compressor |
26 - Seatbelt chimes / Belt retractor / Oil pressure indicator / Sunroof |
Back to the top |
CIRCUIT OPERATION
Seatbelt Chimes
With the seatbelt unbuckled, the "FASTEN BELTS" sign lights for 4 to 8 seconds, and the chimes sound for the same length of time.
With the seatbelt buckled, the "FASTEN BELTS" sign lights for 4 to 8 seconds.
Seatbelt Retractors
When the seatbelt is pulled out and buckled, the switch in the lap belt retractor is closed. The retractor solenoid in the belt housing is energized and the 15 second timer starts counting down. When the 15 seconds are up or when the seatbelt is buckled, current to the solenoid is interrupted. The interia reel locks.
When the seatbelt is unbuckled, the inertia reel is automatically unlocked.
TROUBLESHOOTING
LIGHT AND CHIMES DON'T WORK
- Observe PARKING BRAKE WARNING LIGHT to check fuse.
- Check TIMER connections
- Check voltage at TIMER.
SEATBELT CHIMES DON'T SOUND
- Check seatbelt switch continuity to ground.
SUNROOF WON'T OPEN
- Shift transmission to reverse. Observe BACKUP LIGHTS to check B/U TRANS Fuse.
- Check connections at SUNROOF SWITCH:
-- C176 (PNK wire) - Input Voltage
-- C177 (LT GRN wire) - Motor Lead
-- C177 (BLK wire) - Motor Lead
- Connect C176 (BLK wire) to ground. Operate SUNROOF.
COMPONENT LOCATION
| Page/Figure | ||
| Lap Belt Retractor | Side floor panel | 26-2 |
| Seatbelt Switch | Inner front seat | 26-2 |
| Seatbelt Warning Chimes | Forward side of glove box liner | 26-1 |
| Seatbelt Warning Timer | Dash harness, near transmission downshift switch | 17-1 |
| Shoulder Belt Retractor Solenoid | Quarter inner panel | 26-2 |
| Sunroof Motor | Center of windshield header area | 26-3 |
C103, C103B |
Bulkhead, behind fuse block | 5-1 |
| C115 | Right dash wiring | 26-1 |
| C122 | Fuse block dash harness | 5-1 |
| C133 | Near fuse block | 26-3 |
| C176 | Center of front roof panel, near sunroof switch | |
| C177 | Center of front roof panel, near sunroof switch | 26-3 |
| C178 | Seatbelt retractor harness at console | 26-2 |
| C201A | Fuse panel dash harness | 5-1 |
| C211 | Right front door and seat harness at right "B" pillar | 20-1 |
| C211B | Seatbelt retractor harness at right "B" pillar | 26-2 |
| C213 | Cross body harness at right "P" pillar | 20-1 |
| C222 | Seatbelt retractor harness under left dash | 5-1 |
27 - Radio / Digital clock / Power antenna |
Back to the top |
CIRCUIT OPERATION
With the IGNITION SWITCH in "Accy" or "Run", voltage is applied through the RADIO FUSE to the "On-Off" switch in the DIGITAL CLOCK/RADIO. Voltage is applied at all times through FUSIBLE LINK C and the ANT FUSE to the ANTENNA RELAY.
When the "On-Off" switch is turned "On", current flows through the RADIO FUSE into the solid state radio and also through the PNK wire and the ANTENNA RELAY coil to ground. Current through the radio powers the speakers and the digital clock display. The radio station call numbers light up on the digital clock display for about 5 seconds. The relay operates. Current flows through the ANT FUSE, ORN/BLK and ORN wires, ANTENNA RELAY contacts (4) and (3), DK GRN wire, ANTENNA MOTOR ("Up" contacts), GRY wire, and relay terminals (1) and (5) to ground. The antenna moves up. The ANTENNA MOTOR "DN" contacts close when the antenna starts up. The "Up" contacts open when the antenna is fully up.
When the "On-Off" switch or IGNITION SWITCH is turned "Off", current no longer flows through the DIGITAL CLOCK/RADIO, or the relay coil. Current flows through the ANT FUSE, relay terminals (4) and (2), WHT wire, motor ("Dn" contacts), and relay terminals (3) and (5) to ground. The antenna moves down. The "Dn" contacts open when the antenna is fully down.
Voltage is available at all times through FUSIBLE LINK A and the CLK-LTR FUSE to the DIGITAL CLOCK. This is used to power the clock itself and other memory-related functions like the push button station settings.
Voltage is available at all times through the TAIL LIC FUSE to LIGHT SWITCH terminal 5. With the LIGHT SWITCH in "Park" or "Head", a control voltage is applied through terminal 4, the CRN PRK FUSE, and BRN wires to the DIGITAL CLOCK. Current also flows through terminal 4, the INST LPS FUSE, GRY/BLK wires, LIGHT SWICH terminal 3, dimmer control, and GRY wires to the DIGITAL CLOCK. This current controls the brightness of the digital display. The digital display is normally powered through the RADIO FUSE.
TROUBLESHOOTING
RADIO DOESN'T WORK
- Operate POWER ANTENNA to check voltage to RADIO.
- Connect RADIO (terminal G) to ground and operate RADIO.
ONE SPEAKER DOESN'T WORK
- Check speaker connections (C110 for front speakers, A and B at rear speakers).
IGNITION NOISE
- Replace NOISE SUPPRESSION CAPACITOR (DISTRIBUTOR).
POWER ANTENNA DOESN'T WORK
- Operate RADIO to check RADIO FUSE.
- To check CLK LTR ANT FUSE, check to see if clock is running.
- With the ANTENNA CONTROL pushed to Up, check voltages at ANTENNA RELAY (terminals 6, 4, and 3).
- Connect ANTENNA RELAY (terminal 5) to ground and operate POWER ANTENNA.
COMPONENT LOCATION
| Page/Figure | ||
| Antenna Motor | Left front fender | 27-2 |
| Antenna Relay | Dash harness, near speedometer instrument panel | 27-1 |
C103 |
Bulkhead, behind fuse block |
5-1 |
| C103B | Bulkhead, engine harness | 5-1 |
| C109 | Under left dash | 12-2 |
| C110 | Dash harness near radio | 17-2 |
| C153 | Near power antenna motor | 27-2 |
| C168 | behind radio | 17-2 |
28 - Automatic climate control |
Back to the top |
CIRCUIT OPERATION
The AUTOMATIC CLIMATE CONTROL is an electro-mechanical-vacuum system which maintains a set in-car temperature.
The PROGRAMMER AMPLIFIER senses the difference between the in-car temperature and the set temperature.
If the in-car temperature is warmer than the set temperature, the outside air is cooled as it enters the car (except in Econ). If the in-car air is cooler than the set temperature, the incoming air is warmed.
If the AMPLIFIER senses a big difference between the in-car air temperature and the set temperature, it commands the blower to work at high speed. As the difference between the two temperatures is reduced, the AMPLIFIER slows the BLOWER speed.
Electrical commands from the AMPLIFIER are changed into vacuum or mechanical movements by the TRANSDUCER.
COMPONENT LOCATION
| Page/Figure | ||
| Ambient Temperature Sensor | Mounted on plenum surface | 28-1 |
| ATC Programmer | Mounted on A/C module | 28-1 |
| Blower Motor | Mounted on evaporator assembly, to right of cowl | 28-2 |
| Blower Relay | Mounted on evaporator assembly, to right of cowl | 28-2 |
| Clutch Coil | Mounted on compressor front head | 28-4 |
| Compressor Low Pressure Cutout Switch | Mounted in compressor rear head | 28-5 |
| Heater Temperature Switch | Left bottom rear of engine | 28-4 |
| Idle Air Compensator | Back of throttle assembly | 28-3 |
| In-car Temperature Sensor | Instrument panel cover | |
| RANCO Switch | On A/C-heater module | 28-6 |
C103 |
Bulkhead, behind fuse block |
5-1 |
| C103B | Bulkhead, engine harness | 5-1 |
| C108 | Center dash harness | 28-1 |
| C110 | Upper panel cover wiring near digital clock | 17-1 |
| C116 | Dash harness, near cruise controller | 5-1 |
| C125 | ATC control | 28-7 |
| C126 | ATC control | 28-7 |
29 - Horn / Downshift solenoid |
Back to the top |
TROUBLESHOOTING
HORNS DON'T WORK
- Operate POWER DOOR LOCKS to check HORN CIRCUIT BREAKER.
- Check voltage at C134 (BLK wire).
ONE HORN DOESN'T WORK
- Check horn ground connection.
- Check voltage at horn connector.
COMPONENT LOCATION
| Page/Figure | ||
| Backup Light Switch | Base of steering column | 14-1 |
| Downshift Solenoid | Mounted on transmission | |
| Downshift Switch | Above accelerator | 29-1 |
| Horn Relay | Dash harness, near fuse block | 5-1 |
| Horns | Right front fender | 9-1 |
C102 |
Steering column |
14-1 |
| C103 | Bulkhead, behind fuse panel | 5-1 |
| C103B | Bulkhead, engine harness | 5-1 |
| C134 | Right front fender | 9-1 |
30 - Grounds |
Back to the top |
31 - Trunk pull down |
Back to the top |
CIRCUIT OPERATION
Closing Cycle (Pull Down)
The HOOK-STRIKER SWITCH closes as the trunk lid is lowered. Current flows through the WDO CIRCUIT BREAKER and energizes the PULL DOWN RELAY. The PULL DOWN MOTOR runs until the PLUNGER SWITCH B opens.
Opening Cycle (Reset)
The TRUNK LID SWITCH UNIT PLUNGER SWITCH A closes as the trunk lid starts up. Current flows through the closed PULL DOWN RELAY contacts, operating the PULL DOWN MOTOR. Tile striker is driven to its full up position. As the striker reaches its full up position, the UP-CYCLE CUTOUT SWITCH opens, stopping the PULL DOWN MOTOR.
TROUBLESHOOTING
TRUNK PULL DOWN DOESN'T WORK
- Check PULL DOWN RELAY is grounded.
- Operate POWER WINDOWS to check WDO CIRCUIT BREAKER.
COMPONENT LOCATION
| Page/Figure | ||
| Hood-Striker Switch | Part of striker pull down unit | 31-1 |
| Pull-Down Motor | Right rear of trunk | 31-1 |
| Pull-Down Relay | Attached to pull down motor | 31-1 |
| Trunk Lid Switch Unit | Part of striker pull down unit | 31-1 |
| C114 | Dash harness near fuse block | 5-1 |
| C214 | Dash harness near fuse block | 5-1 |
| C214A | Dash harness near fuse block | 18-1 |
32 - Automatic door locks |
Back to the top |
CIRCUIT OPERATION
Manual Locking
When either FRONT DOOR LOCK SWITCH is pressed to Lock, current flows through the LT BLU wire to the DOOR LOCK RELAY. After the DOOR LOCK RELAY is energized, current flows from the ORN/BLK wire, through the relay contacts, through the GRY wires, through the DOOR LOCK MOTORS, through the TAN wires, and to ground through the UNLOCK side of the DOOR LOCK RELAY.
NOTE: Current flows trough the motors in one direction to lock, and in the opposite direction to unlock.
In the "at rest" position, the LOCK and the UNLOCK contacts of the relay are both grounded.
Automatic Locking
When the transmission shift lever is in D, the TRANSMISSION GEAR SWITCH closes. This connects the Lock Enable (drive) input to ground, and enables the AUTOMATIC DOOR LOCK CONTROLLER. When the driver is seated, the DRIVER'S SEAT SWITCH closes. With the COURTESY LIGHTS off and all the doors closed (all switches turned off), the Lock Enable (doors closed) terminal is ungrounded. With the driver seated, all the doors closed, and the shift lever in D, current flows through the ORN wire to the Power Supply terminal of the AUTOMATIC DOOR LOCK CONTROLLER. Current flows from the Lock Power terminal, through the YEL/BLK wire and the DRIVER'S SEAT SWITCH to the DOOR LOCK RELAY. All of the doors are automatically locked.
Automatic Relock Feature
When any door is opened (or the COURTESY LIGHTS turned on) with the driver seated and the gear lever in D, the Lock Enable (doors closed) terminal on the AUTOMATIC DOOR LOCK CONTROLLER is grounded. When the door is shut, the Lock Enable (door closed) terminal is ungrounded and the door is automatically locked by the AUTOMATIC DOOR LOCK CONTROLLER.
TROUBLESHOOTING
NO POWER DOOR LOCKS WORK
- Sound the HORN to check the circuit breaker. Open the doors and observe the COURTESY LIGHTS to check the BODY FUSE.
- Press either FRONT DOOR LOCK SWITCH to Lock and check for voltage at the LT BLU and GRY wires on the DOOR LOCK RELAY.
DOORS DON'T LOCK AUTOMATICALLY
- Actuate the DRIVER SEAT SWITCH. Shift the transmission gear lever in D. Check for voltage at the AUTOMATIC DOOR LOCK CONTROLLER ORN/BLK wires.
DOORS WON'T UNLOCK BY ACTUATING FRONT DOOR HANDLE SWITCHES
- Lock the doors. Actuate the DRIVER SEAT SWITCH. Place the gear lever in P, R, or N. Ground the AUTOMATIC DOOR LOCK CONTROLLER LT BLU wire and witch for unlocking of doors. Check for voltage at the AUTOMATIC DOOR LOCK CONTROLLER, ORN and BLK.YEL wires.
Figure 32-1 - Left or Right Door Handle
Figure 32-2 - Crossbody Harness (Automatic Door Locks)
Figure 32-3 - Base of RH "A" Pillar
COMPONENT LOCATION
| Page/Figure | ||
| Automatic Door Lock Controller | Right front shroud side panel | 32-2 |
| Door Handle Switch | Base of front door inside handle | 32-1 |
| Door Lock Motor | In doors | 20-1, 20-2 |
| Door Lock Relay | Base of right "A" pillar | 22-1 |
| Driver's Seat Switch | Driver's seat | |
| Transmission Gear Switch | Part of backup light switch | 32-2 |
C101 |
Fuse block |
5-1 |
| C114 | Dash harness near fuse block | 5-1 |
| C181 | Automatic door lock harness, at right "A" pillar | 32-2 |
| C201A | Cross body harness at fuse block | 5-1 |
| C205 | Cross body harness at left "A" pillar | 20-2 |
| C206 | Cross body harness at right "A" pillar | 20-1 |
| C209 | Right rear door harness, at "B" pillar | 20-1 |
| C210 | Left rear door harness, at "B" pillar | 20-2 |
| C212 | Cross body harness at left "A" pillar | 20-2 |
| C213 | Cross body harness at right "A" pillar | 20-1 |
| C213B | Automatic door lock harness at right "A" pillar | 20-1 |
| C214 | Cross body harness at fuse block | 5-1 |
| C234 | Automatic door lock harness at right "A" pillar | 32-2 |
| C235 | Automatic door lock harness at left "A" pillar | 32-2 |
33 - Power mirrors |
Back to the top |
CIRCUIT OPERATION
Voltage is available at all times at the LEFT MIRROR SWITCH and the RIGHT MIRROR SWITCH. To raise the left mirror, the LEFT MIRROR SWITCH is pushed to UP. Current flows through the BODY FUSE, LEFT MIRROR SWITCH, YEL wire, LEFT MIRROR MOTOR, LT GRN wire, the LEFT MIRROR SWITCH and BLK wire to ground.
With the LEFT MOTOR SWITCH in DN, current flows through the motor in the opposite direction to lower the mirror.
TROUBLESHOOTING
EITHER MOTOR DOESN'T WORK
- To check the BODY FUSE, turn on COURTESY LIGHTS.
- Check for voltage at mirror switch (ORN wire).
- Push switch to UP and check for voltage at switch (YEL wire).
- Push switch to UP and check for continuity to ground at switch (LT GRN wire).
- Connect a wire from switch (BLK wire) to ground. Push switch to UP and check for motor operation
COMPONENT LOCATION
| Page/Figure | ||
| Left Mirror Switch | On left side of armrest | |
| Mirror Motors | Inside of power mirror assembly | 33-1 |
| Right Mirror Switch | Center of instrument panel | 33-1 |
C101 |
Fuse block |
5-1 |
| C201A | Front body harness, at fuse block | 5-1 |
| C212 | Crossbody harness at left "A" pillar | 20-2 |
| C212A | Left front door harness, at left "A" pillar | 20-2 |
| C213 | Cross body harness at right "A" pillar | 20-1 |
| C213A | Right front door harness, at right "A" pillar | 20-1 |
| C284 | Right front door power remote mirror harness | 33-1 |
| C285 | Left front door power remote mirror harness | 33-1 |
| C286 | Right front door power remote mirror harness | 33-1 |
| C287 | Left front door power remote mirror harness | 33-1 |
34 - Diesel engine: Charge / pre-ignition |
Back to the top |
CIRCUIT OPERATION
The diesel engine has two batteries which provide extra starting power. They are directly connected to the GENERATOR BAT terminal for charging. Power Distribution is made through the JUNCTION BLOCK in the same way as with the gasoline engine (see chapter 04).
The GLOW PLUG CONTROL RELAY contacts are hot at all times. With the IGNITION SWITCH in "Run", the following takes place:
1) Current flows through the IGNITION SWITCH, C103B and the FUEL SOLENOID (to ground). This operates the solenoid, which turns on the fuel flow.
2) Current flows through the CRUISE A/C FUSE, "Gen" indicator bulb, BRN wire, DIODE, and GENERATOR terminal 1 (to ground). The "Gen" bulb goes on.
3) Current flows through the GAUGES FUSE, "Wait" indicator bulb, INDICATOR CONTROL RELAY A contacts, and the INSTRUMENT PANEL GROUND. The "Wait" bulb goes on. Voltage is applied at the same time through the "Start" bulb and the indicator relay C contacts. Current does not flow through te "Start" bulb.
4) Current flows through the B/U FUSE, and follws two paths to ground. One is through the FAST IDLE RELAY and FAST IDLE SOLENOID (to ground). The other path is through GLOW PLUG CONTROLLER switches A, B and C, the YEL wire, and the GLOW PLUG CONTROL RELAY coil to the INSTRUMENT PANEL GROUND. Voltage is now applied to both sides of the coil in the INDICATOR CONTROL RELAY (through the WHT and YEL wires).
The current through the GLOW PLUG CONTROL RELAY coil closes the normally open switch. Full battery power flows through the RED wire, relay switch, and both the LH and RH BANK GLOW PLUGS. These are pulsing currents (not constant). The .5 ohm timing element in the controller constantly opens and closes switch A. This in turn makes the switch in the glow plug relay do the same.
CAUTION: Do not apply a constant 12 volts to the glow plugs, or they will be damaged.
When the 30 and 20 ohm timing elements in the controller heat up, switch B opens. This breaks the current through the YEL wire and the glow plug relay. The relay contacts open, and the glow plugs stop heating. Current flows through the indicator relay coil to the INSTRUMENT PANEL GROUND. Current flows in that path for an instant, and indicator relay B and D contacts close. Current through the WHT wire now flows through the relay B contacts, and directly to the INSTRUMENT PANEL GROUND. This breaks the current flow through the "Wait" indicator bulb. Current now flows instead through the "Start" bulb, TAN wire, relay D contacts, the DIODE, and GENERATOR terminal 1 (to ground). The "Wait" bulb goes out and the "Start" bulb goes on.
When the engine starts, the IGNITION SWITCH is returned to "Run". 12 volts is now applied from GENERATOR terminal 1, and the BRN wire to the DIODE. This voltage prevents current flow through the "Gen" and "Start" bulbs.
The 20 ohm timing element receives current through the RED wire, GLOW PLUG CONTROL RELAY, BLK wire, FUSIBLE LINK D, and the ORN wire. In "Run", current from GENERATOR terminal 1 and the BRN wire flows through the 130 ohm timing element. It keeps the circuit through the YEL wire open by opening controller switch C.
The FAST IDLE SOLENOID operates whenever the engine is cold, or the air conditioner compressor is on. When the engine coolant goes above 120°F (49°C), the COOLANT TEMPERATURE SWITCH closes. Current flows through the DK GRN wire and the FAST IDLE RELAY coil (to ground). The relay contacts close. the solenoid stops operating unles the air conditioner compressor is on.
TROUBLESHOOTING
See Cadillac Service Manual, Section 6.
COMPONENT LOCATION
| Page/Figure | ||
| Coolant Temperature Switch | Top front of engine | 34-1 |
| Diode | Taped to engine harness at left side of cowl | 34-2 |
| Fast Idle Relay | Left side of cowl | 34-2 |
| Fast Idle Solenoid | Top front of engine | 34-1 |
| Fuel Solenoid | Top front of engine | 34-1 |
| Glow Plug Controller | Top front of engine | 34-1 |
| Glow Plug Controll Relay | Right fender above wheelwell | 34-3 |
| Indicator Control Relay | Left side of cowl | 34-3 |
C103 |
Bulkhead, behind fuse block |
5-1 |
| C103B | Bulkhead, behind fuse block | 5-1 |
| C116 | Under dash | 5-1 |
| C179 | Right rear of engine | 34-3 |
| C182 | Right rear of engine | 34-3 |
35 - Diesel engine: Automatic Climate Control |
Back to the top |
CIRCUIT OPERATION
If the car has a diesel engine, the PPL wire connects to the COMPRESSOR CUTOUT RELAY. The voltage is applied to the A/C COMPRESSOR CYCLING SWITCH. If both the cycling switch and A/C PRESSURE CUT-OUT SWITCH are closed, current flows through the cycling switch, A/C COMPRESSOR CLUTCH, and low pressure switch (to ground), The compressor operates.
Voltage through the COMPRESSOR CUT-OUT RELAY is also applied to the open contacts of the FAST IDLE RELAY. The FAST IDLE SOLENOID opperates in "Run" or "Start" whenever the engine is cold, or the air conditioner compressor is on. When the engine coolant goes above 120°F (49°C), the COOLANT TEMPERATURE SWITCH closes. Current flows through the B/U FUSE, temperature switch, DK GRN wire, and FAST IDLE RELAY coil (to ground). The relay contacts close. The solenoid stops operating unless it receives power through the COMPRESSOR CUT-OUT RELAY.
Current flow through the cut-out relay can be broken by current through the relay coil. If the DOWNSHIFT SWITCH closes, current flows through the B/U TRANS FUSE, switch, and relay coil (to ground). The relay contacts open and current flow stops. In the diesel engine the DOWNSHIFT SWITCH does not operate a downshift solenoid as it does for gasoline engine cars.
COMPONENT LOCATION
| Page/Figure | ||
| A/C Compressor Clutch | Mounted on compressor front head | 28-4 |
| Backup Light Switch | Base steering column | 14-1 |
| Compressor Cut-Out Relay | Mounted under dash on stabilizer brace rod support | 35-1 |
| Compressor Low Pressure Cut-Out Switch | Mounted in compressor rear head | 28-5 |
| Coolant Temperature Switch | Right front of engine | 34-1 |
| Downshift Switch | Accelerator pedal bracket | |
| Fast Idle Relay | Left side of cowl | 34-2 |
| Fast Idle Solenoid | Part of throttle body | 34-1 |
| RANCO Switch | Mounted on evaporator assembly to right of cowl | 28-6 |
C103B |
Bulkhead engine harness |
5-1 |
| C179 | Top right rear of engine (diesel only) | 28-6 |
| C180 | Under right side of instrument panel near A/C module (diesel engine only) | 17-2 |
36 - Trip computer / Power seat recliner |
Back to the top |
CIRCUIT OPERATION
The TRIP COMPUTER uses a MICRO COMPUTER to gather and process information about the car's operation. It provides information to the driver through the DISPLAY HARNESS ASSEMBLY and three Transistorized displays: FUEL DISPLAY, SPEED DISPLAY, and DATA CENTER.
The DATA CENTER displays data as they are entered by the driver. It also displays readout calculations, time of day, and car operation data.
The KEYBOARD is used by the driver to call up information in the DATA DISPLAY
The ENGLISH/METRIC CONVERSION SWITCH directs the computer to receive and read out information in one or the other system of measure. It controls the computer and all three displays.
The SEAT RECLINER MOTOR is a single winding motor. Current flows through the motor in one direction to recline the seat back, and in the opposite direction to raise the seat back.
Voltage is available at all times at the SEAT RECLINER SWITCH. With the switch pushed to Dn, current flows through the HORN CIRCUIT BREAKER, the momentarily closed Dn switch, the SEAT RECLINER MOTOR, and to ground through the Up side of the SEAT RECLINER SWITCH.
With the SEAT RECLINER SWITCH pushed to Up, current flows in the opposite direction through the motor to raise the seat back.
TROUBLESHOOTING
POWER SEAT RECLINER DOESN'T WORK
- Sound HORN to check circuit breaker.
- Check voltage at SEAT RECLINER SWITCH (ORN/BLK wire).
- Push switch to Dn. Check voltage at switch (LT GRN wire).
- Connect both BLK wires at the switch to ground. Check for operation of the SEAT RECLINER MOTOR.
- Check connections at the SEAT RECLINER MOTOR (two LT GRN wires).
COMPONENT LOCATION
| Page/Figure | |||
| Coolant Temperature Sensor | Top front of engine (Gasoline) (Diesel) |
36-1 34-1 |
|
| Cruise Controller | Under dash | 24-1 | |
| Electrinic Control Unit (EFI system) | Under dash, near radio | 6-3 | |
| Fuel Tank Sender | Fuel tank | 6-4 | |
| In-Line Fuses | At microcomputer | ||
| Microcomputer | Under right side of dash | 6-5 | |
| Seat Recliner Motor | Inside seat | 21-1 | |
| Speed Sensor | Part of distributor | 5-3 | |
| Speed Sensor Buffer Amplifier | Taped to microcomputer sensor wiring harness under left side of dash | 6-5 | |
C101 |
Fuse block |
5-1 |
|
| C103 | Behind fuse block | 5-1 | |
| C103B | Behind fuse block | 5-1 | |
| C109 | Dash harness, near light switch | 11-2 | |
| C114 | Dash harness near fuse block | 5-1 | |
| C130 | EFI electronic control unit | 6-3 | |
| C132 | EFI electronic control unit | 6-3 | |
| C160 | Under right side of dash, near microcomputer | 36-1 | |
| C161 | Under right side of dash, near microcomputer | 36-1 | |
| C162 | Under left side of dash | 36-1 | |
| C163 | Under left side of dash | 36-1 | |
| C164 | Under left side of dash | 36-1 | |
| C165 | Center of dash at keyboard | 36-1 | |
| C166 | Under left side of dash at cruise controller | 36-1 | |
| C167 | Behind right dash near ash tray | 36-1 | |
| C172 | Under seat, near recliner motor | 21-1 | |
| C183 | At distributor (HEI system) | ||
| C201 | Cross body harness, at fuse block | 5-1 | |
| C202 | Front body harness, at left trunk hinge | 13-2 | |
| C202A | Rear body harness, at left trunk hinge | 13-2 | |
| C205 | Cross body harness | 20-2 | |
| C207 | Left front door and seat harness, under left seat | 20-2 | |
| C214 | Cross body harness, near fuse block | 5-1 | |
| C223 | Near fuel tank | 6-4 |
