Headlights - Automatic Twilight Sentinel Cadillac Eldorado X

DESCRIPTION

Automatic twilight sentinel determines automatic on/off control of exterior lights, and holds exterior lights on for a period of time after ignition switch is turned off. Instrument Panel Cluster (IPC) monitors ambient light condition through the twilight photocell. A twilight delay switch is used to determine the twilight delay after ignition is turned off. Twilight delay can be adjusted in 10-second intervals from 3 to 180 seconds in response to voltage level at twilight delay input. If twilight sentinel switch is turned off during delay period, exterior lights will turn off immediately.

OPERATION

System operates automatically whenever ignition is on, headlights are off, and twilight sentinel system is on. When turned on, system automatically turns on exterior lights at dusk. At dawn, system will turn exterior lights off.

System provides a non-adjustable 20-second delay before switching lights on or off, thus preventing system from operating under sudden ambient lighting changes (such as passing through tunnels or exposure to bright lights at night).

HANDLING PRECAUTIONS

1. Discharge personal static electricity by momentarily touching metal grounding point on vehicle before touching electronic components.
2. DO NOT touch terminals on components or connectors with fingers or metal tools. When unplugging connectors, DO NOT let metal tool contact any exposed terminal.
3. Never jumper, ground, or use test probes on components or connectors unless specified in diagnosis. Always connect ground lead first.
4. DO NOT remove solid-state components from protective packaging until ready for installation. Touch packaging to ground before opening.
5. DO NOT bump or drop components. DO NOT put component on metal work bench, metal objects, or electrically operated components (such as radio, TV, or oscilloscope).

TROUBLE SHOOTING

1. Check HDLPS fuse (20-amp), FOG/DRL fuse (10-amp), MIRROR fuse (10-amp), IGN 1 fuse (10-amp), L HDLP LO fuse (10-amp), R HDLP LO fuse (10-amp), L HDLP HI fuse (10-amp), and R HDLP HI fuse (10-amp) located in engine compartment fuse/relay center. Check DRL fuse (10-amp), if equipped.
2. Check RADIO/PHONE (10-amp) fuse in trunk compartment fuse block. Ensure headlight relay "A", parking lights relay "B", high/low beam headlight relay "C" and DRL relay "F" are securely mounted in engine compartment micro relay center. Ensure all ground connections are clean and tight.
3. Check for poor connections or partially broken wire inside of insulation which could cause an intermittent. Check for proper installation of aftermarket electronic equipment.

DIAGNOSIS & TESTING

Note. Unless otherwise specified, make all measurements with a Digital Volt-Ohmmeter (DVOM) with an input impedance of 10 megohms.

HEADLIGHT SYSTEM TESTS

Note. Body Control Module (BCM) may be referred to as Platform Zone Module (PZM). PZM is located in front of trunk, mounted to electronics bay.

System Check

1. Turn ignition off. Put gearshift lever in Park. Turn twilight sentinel off. Turn headlight switch off. All exterior lights should be off.
2. Turn parking lights on. All parking lights should be illuminated.
3. Turn low beam headlights on. Parking lights should remain lit. Both low beam headlights should be illuminated.
4. Pull multifunction switch on left side of steering column forward. Headlights should switch from low beam to high beam.
5. Pull multifunction switch forward again. Turn headlights off. Turn ignition switch to RUN position. All headlights and parking lights should be off.
6. Apply parking brake. Put gearshift lever in Drive. Expose twilight photocell to sunlight or bright incandescent light. On Concours and DeVille, both low beam headlights should illuminate at reduced intensity. On Eldorado and Seville, both high beam headlights should illuminate at reduced intensity. On all models, all other exterior lights should be off.
7. Put gearshift lever in Park. Turn twilight sentinel on, with twilight sentinel delay in MIN position. Cover twilight photocell. Both low beam headlights should illuminate at full intensity and all parking lights should turn on within 30 seconds.
8. Apply parking brake to clear climate control panel/driver information center. Slowly slide twilight sentinel delay switch from "-" to "+" position. Twilight sentinel delay should change from 3 to 180 seconds in 10-second intervals.
9. Put twilight sentinel delay in MAX position. Turn ignition off. All exterior lights should turn off after about 3 minutes.

Test No. 1, Lights Do Not Turn Off

1. If both headlights and parking lights do not turn off, go to step 9). If only headlights do not turn off, go to next step. If only parking lights do not turn off, locate and repair problem in exterior lighting system. See appropriate wiring diagram in EXTERIOR LIGHTS article.
2. If high beams are on, go to step 5). If low beams are on, remove headlight relay from engine compartment micro relay center (located in front of left strut tower). On Concours and DeVille, if low beams do not turn off, go to step 4). On Eldorado and Seville, if low beams do not turn off, go to next step. If low beams turn off, replace headlight relay.
3. On Eldorado and Seville, repair short to voltage in circuit No. 12 (Tan wire) between high/low beam headlight relay in engine compartment micro relay center and engine compartment fuse/relay center.
4. On Concours and DeVille, remove Daytime Running Lights (DRL) relay from engine compartment micro relay center. If low beams turn off, replace DRL relay. If low beams do not turn off, repair short to voltage in circuit No. 12 (Tan wire) between high/low beam headlight relay in engine compartment micro relay center and engine compartment fuse/relay center.
5. Remove high/low beam headlight relay from engine compartment micro relay center (located in front of left strut tower). If high beams turn off, go to next step. On Concours and DeVille, if high beams do not turn off, go to step 7). On Eldorado and Seville, if high beams do not turn off, go to step 8).
6. Reinstall high/low beam headlight relay. Disconnect PZM 32-pin connector C2. If high beams are on, replace PZM. See «BODY CONTROL MODULE»(/cadillac/eldorado/x-1992-2002/remont/body-cab-control-systems/#body-control-module) article. If high beams are not on, check for short to ground in circuit No. 1969 (Black/White wire) between high/low beam headlight center and PZM. If circuit is okay, replace high/low beam headlight relay.
7. On Concours and DeVille, repair short to voltage in circuit No. 11 (Light Green wire) between high/low beam headlight relay and engine compartment fuse/relay center.
8. On Eldorado and Seville, remove Daytime Running Lights (DRL) relay from engine compartment micro relay center. If high beams turn off, replace DRL relay. If high beams do not turn off, repair short to voltage in circuit No. 11 (Light Green wire) between high/low beam headlight relay and engine compartment fuse/relay center.
9. If both headlights and parking lights do not turn off, connect scan tool. Using scan tool, check IPC headlight switch input. If headlight switch operates properly, go to step 11). If headlight switch does not operate properly, go to next step.
10. Disconnect headlight switch 12-pin connector C1. If headlights and parking lights turn off, replace headlight switch. If headlights and parking lights do not turn off, check for short to ground in circuit No. 10 (Yellow wire) between headlight switch and IPC. If circuit is okay, replace IPC. See «INSTRUMENT PANEL»(/cadillac/eldorado/x-1992-2002/remont/gauges-instrument-panels/#instrument-panel) article.
11. Disconnect IPC 32-pin connector C3. If headlights and parking lights do not turn off, go to next step. If headlights and parking lights turn off, replace IPC.
12. Disconnect PZM 32-pin connector C2. If headlights and parking lights do not turn off, repair short to ground in circuit No. 10 (Yellow wire) between headlight switch and IPC. If headlights and parking lights turn off, replace PZM. See «BODY CONTROL MODULE»(/cadillac/eldorado/x-1992-2002/remont/body-cab-control-systems/#body-control-module) article.

Test No. 2, Headlights & Parking Lights Inoperative

1. Connect scan tool. Using scan tool, check IPC headlight switch input. If headlight switch operates properly, go to next step. If headlight switch does not operate properly, check for open in circuit No. 151 (Black/White wire) between headlight switch and ground. Check for open in circuit No. 10 (Yellow wire) between headlight switch and IPC. If circuits are okay, replace headlight switch.
2. Turn headlight switch on. Disconnect PZM 24-pin connector C1. Using DVOM, check voltage between ground and PZM harness connector C1 terminal B10 (White wire). If battery voltage exists, repair short to ground or open in circuit No. 352 (White wire) between PZM and engine compartment micro relay center (located in front of left strut tower). If battery voltage does not exist, replace PZM. See «BODY CONTROL MODULE»(/cadillac/eldorado/x-1992-2002/remont/body-cab-control-systems/#body-control-module) article.

Test No. 3, Low Beam Headlights Inoperative

1. Connect scan tool. Using scan tool, check IPC headlight switch input. If headlight switch does not operate properly, go to next step. If headlight switch operates properly, go to step 3).
2. Disconnect headlight switch 12-pin connector C1. Connect a fused jumper wire between ground and headlight switch harness connector C1 terminal "C" (Yellow wire). If IPC headlight switch input is on, check for open in circuit No. 151 (Black/White wire) between headlight switch and ground. If circuit is okay, replace headlight switch. If IPC headlight switch input is not on, check for open in circuit No. 10 (Yellow wire) between headlight switch and IPC. If circuit is okay, replace IPC.
3. Remove headlight relay from engine compartment micro relay center (located in front of left strut tower). Using DVOM, check voltage between ground and headlight relay socket terminal D3 (Orange wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair short to ground or open in circuit No. 340 (Orange wire) between headlight relay and engine compartment fuse relay center.
4. Connect a 20-amp fused jumper wire between headlight relay socket terminals D3 (Orange wire) and C1 (Light Blue wire). If low beams turn on, go to next step. If low beams do not turn on, go to step 6).
5. Turn headlight switch on. Disconnect PZM 24-pin connector C1. Using DVOM, check voltage between ground and PZM harness connector C1 terminal B10 (White wire). If battery voltage does not exist, replace PZM. See «BODY CONTROL MODULE»(/cadillac/eldorado/x-1992-2002/remont/body-cab-control-systems/#body-control-module) article. If battery voltage exists, check for open in circuit No. 10 (Yellow wire) between headlight switch and IPC. Check for short to ground or open in circuit No. 352 (White wire) between PZM and headlight relay. If circuits are okay, replace headlight relay.
6. Reinstall headlight relay. Remove high/low beam headlight relay from engine compartment micro relay center. Using DVOM, check voltage between ground and high/low beam headlight relay socket terminal C9 (Orange wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair short to ground or open in circuit No. 40 (Orange wire) between high/low beam headlight relay and trunk compartment fuse block.
7. Turn headlight switch on. Turn headlight dimmer switch to high. Using DVOM, check voltage between high/low beam headlight relay socket terminal C9 (Orange wire) and D7 (Black/White wire). If battery voltage exists, go to next step. If battery voltage does not exist, check for open in circuit No. 1969 (Black/White wire) between high/low beam headlight relay and PZM. If circuit is okay, replace PZM. See «BODY CONTROL MODULE»(/cadillac/eldorado/x-1992-2002/remont/body-cab-control-systems/#body-control-module) article.
8. Connect a 10-amp fused jumper wire between high/low beam headlight relay socket terminals C9 (Orange wire) and C8 (Tan wire). If low beams turn on, replace high/low beam headlight relay. If low beams do not turn on, check for open in circuit No. 1346 (Light Blue wire) between high/low beam headlight relay and headlight relay. Check for open in circuit No. 12 (Tan wire) between high/low beam headlight relay and engine compartment fuse/relay center. Repair as necessary.

Test No. 4, High Beam Headlights Inoperative

1. Turn headlight switch on. Turn high beams on. Remove high/low headlight relay from engine compartment micro relay center (located in front of left strut tower). Using DVOM, check voltage between ground and high/low headlight relay socket terminal C9 (Orange wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair short to ground or open in Orange wire between high/low headlight relay and trunk compartment fuse block.
2. Check voltage between high/low headlight relay socket terminals C9 (Orange wire) and D7 (Black/White wire). If battery voltage exists, go to next step. If battery voltage does not exist, check headlight dim-mer switch. See TEST NO. 5, HEADLIGHT DIMMER SWITCH INOPERATIVE. If headlight dimmer switch is okay, check for open in circuit No. 1969 (Black/White wire) between high/low headlight relay and PZM. If circuit is okay, replace PZM. See «BODY CONTROL MODULE»(/cadillac/eldorado/x-1992-2002/remont/body-cab-control-systems/#body-control-module) article.
3. Connect a 10-amp fused jumper wire between high/low headlight relay socket terminals C9 (Orange wire) and C7 (Light Green wire). If high beams turn on, replace high/low headlight relay. If high beams do not turn on, repair short to ground or open in circuit No. 11 (Light Green wire) between high/low headlight relay and engine compartment fuse/relay center.

Test No. 5, Headlight Dimmer Switch Inoperative

1. Disconnect headlight dimmer switch 48-pin connector C202, located at left side base of steering column. Using DVOM, check voltage between ground and headlight dimmer switch harness connector C202 terminal C4 (Orange wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair short to ground or open in circuit No. 1740 (Orange wire) between headlight dimmer switch and engine compartment fuse/relay center.
2. Reconnect headlight dimmer switch connector C202. Connect scan tool. Select IPC INPUT: HIGH BEAM SWITCH. If headlight dimmer switch does not operate properly, go to next step. If headlight dimmer switch operates normally, check operation of high beams. If high beams do not operate, go to TEST NO. 4, HIGH BEAM HEADLIGHTS INOPERATIVE.
3. Disconnect IPC 24-pin connector C2. Pull and hold multifunction lever. Using DVOM, check voltage between ground and IPC harness connector C2 terminal B8 (Purple wire). If battery voltage exists, replace IPC. If battery voltage does not exist, check for open in circuit No. 524 (Purple wire) between headlight dimmer switch and IPC. If circuit is okay, replace headlight dimmer switch.

Test No. 6, Twilight Sentinel Inoperative

1. Connect scan tool. Using scan tool, check twilight switch input to IPC. If twilight sentinel enable switch operates properly, go to step 3). If twilight sentinel enable switch does not operate properly, go to next step.
2. Disconnect headlight switch 12-pin connector C1. Connect a fused jumper wire between ground and headlight switch harness connector C1 terminal "K" (Yellow/Black wire). If twilight enable switch input is not on, repair open in circuit No. 1784 (Yellow/Black wire) between headlight switch and IPC. If twilight enable switch input is on, check for open in circuit No. 151 (Black/White wire) between headlight switch and ground. If circuit is okay, replace headlight switch.
3. Using scan tool, select twilight photo from IPC data list. Cover twilight photo cell. If twilight photo value is near zero percent, go to step 5). If twilight photo value is not near zero percent, go to next step.
4. Check for short to voltage or open in circuit No. 279 (Black wire) between IPC and twilight photocell. Check for short to ground or open in circuit No. 278 (White wire) between IPC and twilight photocell. If circuits are okay, replace twilight photocell.
5. Expose twilight photocell to sunlight or bright incandescent light. If twilight photo value is not near 100 percent, go to step 4). If twilight photo value is near 100 percent, reverify that symptom still exists. If symptom still exists, replace IPC.

Test No. 7, Twilight Sentinel Delay Inoperative

1. Connect scan tool. Select twilight delay from IPC data list. Slide twilight delay switch to extreme "+" position. If twilight delay value is near 100 percent, go to next step. If twilight delay value is not near 100 percent, go tostep 3).
2. Slowly slide twilight delay switch to extreme "-" position. Percentage should gradually decrease. If sudden, large decreases are observed, replace headlight switch. Check scan tool reading. If twilight delay value is not near zero percent, go to next step. If twilight delay value is near zero percent, reverify that symptom still exists. If symptom still exists, replace IPC.
3. Turn ignition on. Move twilight delay switch to extreme "+" position. Disconnect IPC 32-pin connector C3. Using DVOM, check voltage between ground and IPC harness connector C3 terminal C9 (Black wire). If reading is about 4.4-4.8 volts, go to step 5). If reading is not about 4.4-4.8 volts, go to next step.
4. Check short to ground or open in circuit No. 1783 (Purple wire) between headlight switch and IPC. Check for short to voltage or open in circuit No. 470 (Black wire) between headlight switch and IPC. If circuits are okay, replace headlight switch.
5. Slide twilight delay switch to extreme "-" position. Ensure DVOM is still connected as specified in step 3). If reading is not about 0.2-0.6 volt, go to step 4). If reading is about 0.2-0.6 volt, replace IPC.

Test No. 8, Daytime Running Lights Inoperative

1. Remove Daytime Running Lights (DRL) relay from engine compartment micro relay center (located in front of left strut tower). Turn ignition on. Using DVOM, check voltage between ground and DRL relay socket terminals A9 (Pink wire) and B9 (Orange wire). If battery voltage exists at both terminals, go to next step. If battery voltage does not exist at both terminals, check for short to ground or open in circuit No. 439 (Pink wire) or No. 1640 (Orange wire) between DRL relay and engine compartment fuse/relay center.
2. Check voltage between DRL relay socket terminals A9 (Pink wire) and B7 (Light Green/Black wire). If battery voltage exists, go to next step. If battery voltage does not exist, check for open in circuit No. 592 (Light Green/Black wire) between DRL relay and PZM. If circuit is okay, replace PZM. See «BODY CONTROL MODULE»(/cadillac/eldorado/x-1992-2002/remont/body-cab-control-systems/#body-control-module) article.
3. Connect a 10-amp fused jumper wire between DRL relay socket terminals B9 (Orange wire) and A7 (Gray wire on Concours and DeVille, and Purple wire on Eldorado and Seville). If DRL do not turn on, go to next step. If DRL turn on, replace DRL relay.
4. On Eldorado and Seville, repair short to ground or open in circuit No. 359 (Purple) wire between DRL relay and high beam headlight. On Concours and DeVille, check for short to ground or open in circuit No. 589 (Gray wire) between DRL relay and DRL resistor (located in right front corner of engine compartment, on fender). Check for short to ground or open in circuit No. 12 (Tan wire) between DRL resistor and splice. If circuits are okay, replace DRL resistor.

REMOVAL & INSTALLATION

Disconnect negative battery cable. Twilight sentinel/DRL module plugs directly into headlight switch assembly. To remove control module, remove headlight switch. Remove 2 screws securing module to left switch pod. Remove module and disconnect electrical connectors. To install, reverse removal procedure.

Twilight sentinel photocell is mounted under center front defroster grille. Unsnap defroster grille. Twist photocell counterclockwise to disengage photocell and socket. Unplug connector. To install, reverse removal procedure.

Automatic Twilight Sentinel System Wiring Diagram (Concours & DeVille). Scheme 1

Automatic Twilight Sentinel System Wiring Diagram (Eldorado & Seville). Scheme 2

See also:
• BODY CONTROL MODULE
• INSTRUMENT PANEL