Headlights - Automatic Twilight Sentinel Cadillac DeVille Concours I final

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 ambient light sensor. 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. If twilight sentinel and headlight switch are turned off, ignition switch is on, transmission is not in Park and ambient light sensor detects darkness, a HEADLAMPS SUGGESTED message will appear on instrument panel. When twilight sentinel is on and wipers are turned on for more than 20 seconds, low beam headlights are turned on.

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).

COMPONENT LOCATIONS

COMPONENT LOCATIONS

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).

PRELIMINARY INSPECTION

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. If any fuse is open, repair short to ground in appropriate wire.
2. Check RADIO/PHONE (10-amp) fuse in rear 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. If no problem is found, perform «SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/headlights/#headlights-automatic-twilight-sentinel__system-check) .

SYSTEM CHECK

Using scan tool, check for DTCs. If any DTCs are present, diagnose and repair first. See appropriate BODY CONTROL MODULES article.

1. Turn ignition switch to OFF position. Put gearshift lever in Park position. Turn twilight sentinel to OFF position. Turn headlight switch to OFF position. 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 on. Both low beam headlights should be illuminated.
4. Pull multifunction switch to high beam position. Headlights should switch from low beam to high beam.
5. Pull multifunction switch again to low beam position. 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 ambient light sensor to sunlight or bright incandescent light. On DeVille, both low beam headlights should illuminate at reduced intensity. On Eldorado, 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 ambient light sensor. Both low beam headlights should illuminate at full intensity and all parking lights should turn on within 30 seconds.
8. Slide twilight sentinel delay switch slowly from minimum to maximum 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 switch to LOCK position. All exterior lights should turn off after about 3 minutes.
10. Turn ignition switch to RUN position. Expose ambient light sensor to bright sunlight or bright incandescent light. Turn windshield wipers on. Both low beam headlights and parking lights should turn on after 20 seconds.
11. If system does not operate as indicated, go to appropriate test. See «SYMPTOM INDEX»(/cadillac/deville-concours/i-final-1999-1999/remont/headlights/#headlights-automatic-twilight-sentinel) table under SYSTEM TESTS. If symptom is not listed, go to appropriate wiring diagram in EXTERIOR LIGHTS article or appropriate wiring diagram in HEADLIGHT SYSTEMS & DAYTIME RUNNING LIGHTS article.

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.

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

SYMPTOM INDEX

TEST 1: LOW BEAMS DO NOT TURN OFF

Note. If only parking lights do not turn off, locate and repair problem in exterior lighting system. See appropriate wiring diagram in EXTERIOR LIGHTS article.

1. If both headlights and parking lights do not turn off, go to next step. If only headlights do not turn off, go to step 12 .
2. Connect scan tool. Check Instrument Panel Cluster (IPC) headlight switch input. Turn headlight switch on and off. If switch input is okay, go to next step. If switch input is not okay, go to step 9 .
3. Disconnect IPC Blue 32-pin connector C3. If headlights and parking lights turn off, go to next step. If headlights and parking lights turn do not off, go to step 5 .
4. Replace IPC. Recheck system.
5. Disconnect PZM Brown 32-pin connector C2. If headlights and parking lights turn off, go to next step. If headlights and parking lights do not turn off, go to step 7 .
6. Replace PZM. See appropriate BODY CONTROL MODULES article. Recheck system.
7. Check for short to ground in Yellow wire between headlight switch and IPC. Repair as necessary and recheck. If no problem is found, go to next step.
8. Repair short to power in White wire between PZM and rear compartment relay center. Recheck system.
9. Disconnect headlight switch Black 12-pin connector C1. If parking lights turn off, go to next step. If headlights and parking lights do not turn off, go to step 11 .
10. Replace headlight switch. Recheck system.
11. Check for short to ground in Yellow wire between headlight switch and IPC. Repair as necessary and recheck. If circuit is okay, replace IPC. See appropriate INSTRUMENT PANELS article.
12. Remove high/low beam headlight relay from engine compartment relay center (located in front of left strut tower). If high beams turn off, go to next step. On DeVille, if high beams do not turn off, go to step 14 . On Eldorado, if high beams do not turn off, go to step 16 .
13. Replace high/low beam headlight relay. Recheck system.
14. Remove Daytime Running Lights (DRL) relay from engine compartment relay center. If low beams turn off, go to next step. If low beams do not turn off, go to step 16 .
15. Replace DRL relay. Recheck system.
16. Repair short to voltage in Tan wire between high/low beam headlight relay in engine compartment relay center and engine compartment fuse/relay center. Recheck system.

TEST 2: HIGH BEAMS DO NOT TURN OFF

1. Remove high/low beam headlight relay from engine compartment relay center (located in front of left strut tower). If high beams turn off, go to next step. On Eldorado, if high beams do not turn off, go to step 3 . On DeVille, if high beams do not turn off, go to step 4 .
2. Install high/low beam headlight relay. Disconnect Platform Zone Module (PZM) Brown 32-pin connector C2. If high beams are on, replace PZM. See appropriate BODY CONTROL MODULES article. If high beams are not on, check for short to ground in Black/White wire between high/low beam headlight center and PZM. If circuit is okay, replace high/low beam headlight relay.
3. Remove Daytime Running Lights (DRL) relay from engine compartment relay center. If low beams turn off, replace DRL relay. If low beams do not turn off, go to next step.
4. Repair short to voltage in Light Green wire between high/low beam headlight relay and engine compartment fuse/relay center.

TEST 3: HEADLIGHTS & PARKING LIGHTS INOPERATIVE

1. Connect scan tool. Using scan tool, check Instrument Panel Cluster (IPC) headlight switch input. If headlight switch operates properly, go to next step. If headlight switch does not operate properly, check for open in Black/White wire between headlight switch and ground. Check for open in Yellow wire between headlight switch and IPC. Repair as necessary. If circuits are okay, replace headlight switch.
2. Turn headlight switch on. Disconnect Platform Zone Module (PZM) connector C2. Using DVOM, check voltage between ground and PZM harness connector C2 terminal C9 (Yellow wire). If battery voltage exists, check White wire between PZM terminal C16, parking lights relay terminal A6 and headlight relay terminal D1. Repair as necessary. If circuit is okay, replace PZM. If battery voltage does not exist, repair short to ground or open in Yellow wire.

TEST 4: LOW BEAM HEADLIGHTS INOPERATIVE

1. Connect scan tool. Using scan tool, check Instrument Panel Cluster (IPC) headlight switch input. If headlight switch does not operate properly, go to next step. If headlight switch operates properly, go to step 6 .
2. Remove headlight relay from engine compartment 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 Orange wire between headlight relay and engine compartment fuse relay center.
3. 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 7 .
4. Turn headlight switch on. Disconnect Platform Zone Module (PZM) connector C2. Using DVOM, check voltage between ground and PZM harness connector C2 terminal C9 (Yellow wire). If battery voltage exists, replace PZM. See appropriate BODY CONTROL MODULES article. If battery voltage does not exist, go to next step.
5. Check for open in Yellow wire between headlight relay and PZM. Repair as necessary. If circuit is okay, check for short to ground or open in White wire between PZM, parking light relay and headlight relay. Repair as necessary. If circuits are okay, replace headlight relay.
6. Disconnect headlight switch Black 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 on scan tool is on, check for open in Black/White wire between headlight switch and ground. Repair as necessary. If circuit is okay, replace headlight switch. If IPC headlight switch input on scan tool is not on, check for open in Yellow wire between headlight switch and IPC. Repair as necessary. If circuit is okay, replace IPC.
7. Reinstall headlight relay. Remove high/low beam headlight relay from engine compartment relay center. Using DVOM, check voltage between ground and high/low beam headlight relay socket terminal C9 (Orange/Black wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair short to ground or open in Orange/Black wire between high/low beam headlight relay and rear compartment fuse block.
8. Turn headlight switch on. Turn headlight dimmer switch to high. Using DVOM, check voltage between high/low beam headlight relay socket terminals C9 (Orange/Black wire) and D7 (Black/White wire). If battery voltage exists, go to next step. If battery voltage does not exist, check for open in Black/White wire between high/low beam headlight relay and PZM. If circuit is okay, replace PZM. See appropriate BODY CONTROL MODULES article.
9. Connect a 10-amp fused jumper wire between high/low beam headlight relay socket terminals C9 (Orange/Black wire) and C8 (Tan wire). If low beams turn on, check for open in Light Blue wire between high/low beam headlight relay and headlight relay. Repair as necessary. If circuit is okay, replace high/low beam headlight relay. If low beams do not turn on, check for open in Tan wire between high/low beam headlight relay and engine compartment fuse/relay center. Repair as necessary. If circuit is okay, check for short to ground or open in White wire between PZM, parking light relay and headlight relay. Repair as necessary. If circuits are okay, replace headlight relay.

TEST 5: HIGH BEAM HEADLIGHTS 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 Orange wire between headlight dimmer switch and engine compartment fuse/relay center.
2. Connect 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, go to step 4 .
3. Disconnect Instrument Panel Cluster (IPC) Gray 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 Purple wire between headlight dimmer switch and IPC. If circuit is okay, replace headlight dimmer switch.
4. Turn headlight switch on. Turn high beams on. Remove high/low headlight relay from engine compartment relay center (located in front of left strut tower). Using DVOM, check voltage between ground and high/low headlight relay socket terminal C9 (Orange/Black 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 rear compartment fuse block.
5. Check voltage between high/low headlight relay socket terminals C9 (Orange/Black wire) and D7 (Black/White wire). If battery voltage exists, go to next step. If battery voltage does not exist, check headlight dimmer switch. Replace as necessary. If headlight dimmer switch is okay, check for open in Black/White wire between high/low headlight relay and Platform Zone Module (PZM). If circuit is okay, replace PZM. See appropriate BODY CONTROL MODULES article.
6. Connect a 10-amp fused jumper wire between high/low headlight relay socket terminals C9 (Orange/Black 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 Light Green wire between high/low headlight relay and engine compartment fuse/relay center.

TEST 6: HEADLIGHTS INOPERATIVE WITH WIPERS ON

Note. When wipers are turned on, low beam headlights should illuminated.

1. Turn twilight delay switch on. Turn ignition switch to on position. Connect scan tool. Select Dash Integration Module (DIM) data. Turn wipers on. Scan tool should indicate lights on with windshield wipers input is on. If data is not as specified, go to next step. If data is as specified, replace body control module (PZM).
2. Check for open or short to ground in Gray wire between connector S210 and instrument panel. Repair as necessary. If no problem is found, repair wiper system. See appropriate WIPER/WASHER SYSTEMS article.

TEST 7: TWILIGHT SENTINEL INOPERATIVE

1. Connect scan tool. Using scan tool, check twilight switch input to Instrument Panel Cluster (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 Black 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 Yellow/Black wire between headlight switch and IPC. If twilight enable switch input is on, check for open in 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 ambient light sensor. If twilight photo value is near 255 counts, go to step 5 . If twilight photo value is not near 255 counts, go to next step.
4. Check for short to power or open in Black wire between IPC and ambient light sensor. Check for short to ground or open in White wire between IPC and ambient light sensor. If circuits are okay, replace ambient light sensor.
5. Expose ambient light sensor to sunlight or bright incandescent light. If twilight photo value is not near zero counts, go to step 4 . If twilight photo value is near zero counts, verify symptom still exists. If symptom still exists, replace IPC.

TEST 8: 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 255 counts, go to next step. If twilight delay value is not near 255 counts, go to step 3 .
2. Slowly slide twilight delay switch to extreme "-" position. Counts should gradually decrease. If sudden, large decreases are observed, replace headlight switch. Check scan tool reading. If twilight delay value is not near zero counts, go to next step. If twilight delay value is near zero counts, verify that symptom still exists. If symptom still exists, replace IPC.
3. Turn ignition switch to RUN position. Move twilight delay switch to extreme "+" position. Disconnect Instrument Panel Cluster (IPC) Blue 32-pin connector C3. Using DVOM, check voltage between ground and IPC harness connector C3 terminal D12 (Black wire). If 4.4-4.8 volts exists, go to step 5 . If 4.4-4.8 volts does not exist, go to next step.
4. Check for short to ground or open in Purple wire between headlight switch and IPC. Check for short to voltage or open in 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 0.2-0.6 volt exists, go to step 4 . If 0.2-0.6 volt does not exist, replace IPC.

TEST 9: DAYTIME RUNNING LIGHTS INOPERATIVE

1. Remove Daytime Running Lights (DRL) relay from engine compartment relay center (located in front of left strut tower). Turn ignition switch to RUN position. Using DVOM, check voltage between ground and DRL relay socket terminals A9 (Pink wire) and B9 (Orange/Black wire on DeVille; Orange wire on Eldorado). 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 appropriate wire between DRL relay and engine compartment fuse/relay center.
2. Ensure shifter is in Park. 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 Light Green/Black wire between DRL relay and Platform Zone Module (PZM). If circuit is okay, replace PZM. See appropriate BODY CONTROL MODULES article.
3. Connect a 10-amp fused jumper wire between DRL relay socket terminals B9 (Orange/Black wire on DeVille; Orange wire on Eldorado) and A7 (Purple wire on DeVille; Purple/White wire on Eldorado). If DRL do not turn on, go to next step. If DRL turn on, replace DRL relay.
4. On Eldorado, repair short to ground or open in Purple/White wire between DRL relay and high beam headlight. On DeVille, check for short to ground or open in Purple wire between DRL relay and DRL resistor. DRL resistor is located in right front corner of engine compartment, on fender. Check for open in Tan/White wire between DRL relay and DRL resistor. Also, check for short to ground or open in Tan wire between DRL fuse and splice. Repair as necessary. If circuits are okay, replace DRL resistor.

REMOVAL & INSTALLATION

Ambient light sensor is mounted under center front defroster grille. Unsnap defroster grille. Twist sensor counterclockwise to disengage sensor and socket. Unplug connector. To install, reverse removal procedure.

WIRING DIAGRAMS

Note. For twilight sentinel system wiring diagrams, see HEADLIGHT SYSTEMS & DAYTIME RUNNING LIGHTS article.

See also:
• SYSTEM CHECK
• SYMPTOM INDEX
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