Home ReviewsRefund
Home/Cadillac/Brougham/Cadillac Brougham I (1987-1992)/Repair manual/Headlights/Headlights - Automatic Twilight Sentinel
Contents Section: Headlights All sections

Headlights - Automatic Twilight Sentinel Cadillac Brougham I

Headlights ~2924 words

DESCRIPTION

The twilight sentinel system automatically controls on-off operation of headlights, taillights, and instrument panel lights in response to ambient light. A time delay control allows lights to remain on for a preselected period after ignition is turned off.

A photocell is mounted face up under speaker or defroster grille. An amplifier unit is mounted on lower instrument panel brace. A time delay and on-off switch is attached to light switch behind the light switch knob.

AUTOMATIC OPERATION

Twilight sentinel system will operate automatically when ignition switch is in "ON" position or headlight switch is in "OFF" position and the control ring pointer is turned on. System will automatically activate lights when level of available light corresponds to dusk.

At daybreak, system will turn lights off. Sudden changes in lighting such as passing through tunnels or under bright lights will not cause system to cycle, due to a 10-60 second delay before amplifier switches system on or off.

A variable time-delay switch control permits the driver to select a delay period before headlights turn off. This can be a few seconds to a maximum of 4 1/2 minutes after ignition switch is turned off.

Additional lighting may be provided (during this period) by turning on cornering lights (if equipped). All lights will turn off automatically at end of time-delay period selected by driver.

MANUAL OPERATION

If lights are to be used during daylight hours, 2 methods may be used. If photocell assembly is covered, lights will turn on. This allows lights to be turned off in normal manner when ignition is off. Lights can also be turned on using regular light switch after turning time-delay switch to "OFF" position.

SENSITIVITY ADJUSTMENT

Note. Sensitivity adjustment is possible on Toronado only.

Toronado

  1. Adjusting screw is reached through a hole in right side of amplifier. Each mark around the hole represents about 5 minutes of daylight. Turn screw clockwise to make lights turn on earlier and counterclockwise for later (darker) in the evening.
  2. To test photocell, measure voltage to ground with a digital meter at White wire of photocell. It should vary from less than 2 volts with the photocell covered to more than 9 volts in bright light.

HEADLIGHTS TURN ON LATE OR EARLY IN EVENING OR MORNING

Defective photocell. Incorrect sensitivity adjustment (Toronado only).

LIGHTS DO NOT TURN ON IN DARKNESS

Loose connection at light switch or amplifier connector. Open wiring between fusible link and light switch. Inoperative light switch (circuit breaker). Open ground path through on-off switch of time delay control assembly. Inoperative photocell or amplifier.

LIGHTS DO NOT TURN OFF IN DAYLIGHT

Amplifier sensitivity control out of adjustment. Inoperative photocell or amplifier. Poor contact between photocell and socket, or socket disengaged from mounting hole.

LIGHTS DO NOT TURN OFF AFTER IGNITION IS OFF

Ignition switch wire has power with key off. Fuse blown. Inoperative time delay control. Open wiring in circuit. Inoperative amplifier. Malfunctioning photocell.

LIGHTS DO NOT STAY ON PROPER TIME SPAN AFTER IGNITION IS OFF

Inoperative time delay control assembly. Blown taillight fuse. Improper resistance at amplifier connector. Short in wiring circuit. Inoperative amplifier.

WARNING CHIME WILL NOT OPERATE

Open wire in chime circuit. Inoperative door jam switch. Poor connection at light switch. Inoperative amplifier. Blown fuse. Time delay control malfunction.

WARNING CHIME SOUNDS WHEN IT SHOULD NOT

Open wire to ignition light switch. Open ground wire to chime module. Malfunctioning amplifier.

SYSTEM TEST

Note. With time-delay control in "ON" position and headlight knob in "OFF" position, check that photocell is not obstructed. Lighting system will work properly when manually operated. Check all fuses for continuity.

  1. With sentinel in "OFF" position, check for proper operation of parking lights, headlights and taillights, using light switch. Place light switch in manual "ON" position with ignition off. Open a door. Warning chime should operate. Turn lights off.
  2. Turn sentinel on after covering photocell. With ignition on, lights should come on automatically within 10-30 seconds. Remove cover and shine a bright light onto photocell.
  3. Light should turn off after a 10-60 second delay. Cover photocell and wait for light to turn on. Wait 15 seconds and turn ignition off. Lights should turn off after a few seconds when control is in off position and after 1 1/2-4 1/2 minutes when control is in maximum position.
  4. Satisfactory performance of steps 1) through 3), indicates unit is operating properly. If unit is operating properly but turn-on time is incorrect, make minor sensitivity adjustment (Toronado only).

Bonneville, Caprice, Delta 88, DeVille, Electra Estate Wagon, Ninety Eight

  1. Disconnect twilight sentinel photocell connector. Turn ignition switch to "RUN" position. Turn twilight sentinel control on. Turn off light switch.
  2. Separate twilight sentinel photocell connector. Lights should come on within 60 seconds. If lights come on within 60 seconds, but do not come on with photocell connected and in darkness, replace photocell. If lights never come on, proceed to, in this section, «TWILIGHT SENTINEL AMPLIFIER TEST»(/cadillac/brougham/i-1987-1992/remont/headlights/#headlights-automatic-twilight-sentinel) .

Eldorado, Riviera, Seville & Toronado

  1. Enter BCM (Body Control Module) diagnostics. Refer to COMPUTERIZED ENGINE CONTROLS article. Select BCM output test BO05. If BCM displays "LO", headlights and exterior lights should come on. If not, perform «TWILIGHT PARK LIGHT RELAY TEST»(/cadillac/brougham/i-1987-1992/remont/headlights/#headlights-automatic-twilight-sentinel) test.
  2. If BCM displays "HI", headlights and exterior lights should be off. If not, perform «TWILIGHT PARK LIGHT RELAY TEST»(/cadillac/brougham/i-1987-1992/remont/headlights/#headlights-automatic-twilight-sentinel) test. If BCM display does not cycle from "LO" to "HI", replace BCM.

Caprice & Electra Estate Wagon

  1. Unplug twilight sentinel amplifier connector behind glove box. Turn ignition switch to "RUN" position. With light switch off, check voltage between Red/White wire and ground. Voltmeter should read battery voltage. If not, check light switch and Red/White wire for open or short.
  2. Connect voltmeter between Red/White and Black wires. Battery voltage should be present. If not, check both wires for open or short.
  3. Connect voltmeter between Orange wire and ground. Battery voltage should be present. If not, check taillight fuse and Orange wire for open circuit.
  4. Connect voltmeter between Pink/White wire and ground. Battery voltage should be present. If not, check Pink/White and Pink wires for open. Check ignition switch.
  5. Turn ignition switch to "OFF" position. Connect voltmeter between Pink/White wire and ground. Voltmeter should read zero volt. If voltage is present, replace ignition switch.
  6. Connect voltmeter between Dark Green/White wire and ground. Voltmeter should read zero volt. If voltage is present, replace light switch.
  7. Connect voltmeter between Yellow wire and ground. Voltmeter should read zero volt. If not, check light switch. Check Orange, Brown, and Dark Green/White wires for open circuit.
  8. Turn park light switch on. Connect voltmeter between Yellow wire and ground. Voltmeter should read zero volt. If not, replace light switch.
  9. Connect voltmeter between Dark Green/White wire. Voltmeter should read battery voltage. If not, check light switch. Check Orange, Brown, and Dark Green/White wire for open.
  10. Turn headlight switch on. Connect voltmeter between Dark Green/White wire and ground. Battery voltage should be present. If not, check light switch. Check the Orange, Brown, and Dark Green/White wires for open circuit.
  11. Connect voltmeter between Yellow wire and ground. Battery voltage should be present. If not, check light switch and Yellow wire for open circuit.
  12. If results were correct from any of the previous steps, reconnect amplifier connector. Turn ignition switch to "RUN" position. Turn light switch off, and twilight sentinel control on.
  13. Connect fused jumper between White and Red/White wires. Headlights should go off within 60 seconds. If not, go to next step. If headlights go off within 60 seconds, but does not go off normally in daylight, check White and Black wires for open, then replace photocell as necessary.
  14. Disconnect amplifier connector. Turn light switch off, disconnect negative battery terminal, and turn twilight sentinel control on.
  15. Connect ohmmeter between Purple wire and ground. Ohmmeter should read zero ohm. If resistance is okay, replace twilight sentinel amplifier. If not, check twilight sentinel control, Purple wire, and ground for open.
  16. Turn twilight sentinel control off. Connect ohmmeter between Purple wire and ground. Ohmmeter should read open circuit. If reading is correct, replace twilight sentinel amplifier. If not, check twilight sentinel control, and Purple wire for short.
  17. Connect ohmmeter between Dark Green/White and Orange wires. Ohmmeter should read zero ohm. If resistance is okay, replace twilight sentinel amplifier. If not, check light switch. Check Orange wire for open.
  18. Turn twilight sentinel control between "MIN" and "MAX" setting. Connect ohmmeter between Black/Yellow and Light Green wires. Ohmmeter should read 500-250,000 ohms (varies with control). If resistance is correct, replace twilight sentinel amplifier. If not, check twilight sentinel control. Check Black/Yellow and Light Green wires for open or short circuit.

Bonneville, Delta 88, DeVille, Fleetwood & Ninety-Eight

  1. Disconnect negative battery terminal. Disconnect twilight sentinel amplifier connector. See «REMOVAL & INSTALLATION»(/cadillac/brougham/i-1987-1992/remont/headlights/#headlights-automatic-twilight-sentinel) in this article for amplifier locations. Turn light switch off. Turn twilight sentinel control on.
  2. Connect ohmmeter between Purple wire and ground. Ohmmeter should read zero ohms. If not, check twilight sentinel control. Check Purple and Black wires for open circuit.
  3. Turn twilight sentinel control off. Connect ohmmeter between Purple wire and ground. Ohmmeter should read open circuit. If not, check twilight sentinel control and Purple wire for short.
  4. Connect ohmmeter between Dark Green/White and Orange wires. Ohmmeter should read zero ohms. If not, check light switch, Orange, and Dark Green/White wires for open circuit.
  5. Turn twilight sentinel control between "MIN" and "MAX" setting. Connect ohmmeter between Black/Yellow and Light Green wires. Ohmmeter should read between 500-250,000 ohms (varies with control). If not, check twilight sentinel control, Black/Yellow, and Light Green wires for open circuit.
  6. If all resistances are correct from the previous steps, reconnect twilight sentinel amplifier connector. Turn ignition switch to "RUN" position. Turn light switch off and twilight sentinel control on.
  7. Connect a fused jumper between White and Black wires. Headlights should go off within 60 seconds. If headlights goes off within 60 seconds but does not go off normally in daylight, check White and Black wires for open, then replace photocell if necessary.
  8. If jumper did not change the condition, disconnect twilight sentinel amplifier connector. Turn ignition switch to "RUN" position, and turn light switch off. Connect voltmeter between Black wire and ground. Voltmeter should read battery voltage. If not, check light switch, and Black wire for open or short.
  9. Connect voltmeter between Black wire on twilight sentinel amplifier and Black wire on twilight sentinel control. Battery voltage should be present. If not, check wires for open circuit.
  10. Connect voltmeter between Orange wire and ground. Battery voltage should be present. If not, check fuse No. 14 and Orange wire for open circuit.
  11. Connect voltmeter between Pink wire and ground. Battery voltage should be present. If not, check Pink wire for open circuit. Check ignition switch.
  12. Turn ignition switch to "OFF" position. Connect voltmeter between Pink wire and ground. Voltmeter should read zero volt. If not, replace ignition switch.
  13. Connect voltmeter between Dark Green/White wire and ground. Voltmeter should read zero volt. If not, replace light switch.
  14. Connect voltmeter between Yellow wire and ground. Voltmeter should read zero volt. If not, replace light switch.
  15. Turn headlight switch on. Connect voltmeter between Yellow wire and ground. Battery voltage should be present. If not, check light switch. Check Yellow wire for open circuit.
  16. Connect voltmeter between Dark Green/White wire and ground. Battery voltage should be present. If not, check wire for open circuit.
  17. If voltages were correct from any of the previous steps, replace the twilight sentinel amplifier.
  1. Enter BCM diagnostics. Select BCM data test BD43. Set twilight sentinel switch to "MIN" position, BCM should display "10". If not, replace left switch assembly. If display was correct, go to step 3).
  2. Set twilight sentinel switch to "MAX" position, BCM should display "90". If not, replace left switch assembly. If displays was correct, go to next step.
  3. Select BCM output test BO05. With BCM displaying "LO", headlights and exterior lights should turn on. With BCM displaying "HI", headlights and exterior lights should turn off. If it does, proceed to «TWILIGHT HEADLIGHT RELAY TEST»(/cadillac/brougham/i-1987-1992/remont/headlights/#headlights-automatic-twilight-sentinel) in this section.
  4. If headlights and exterior lights cycle on and off, go to step 5). If BCM display does not cycle from "LO" to "HI", replace BCM.
  5. Select BCM data test BD44. Expose photocell to bright sunlight or a very bright incandescent light. BCM should display approximately "25" or less. If BCM display value is correct, replace BCM. If not, go to step 7).
  6. Cover photocell with cardboard. BCM should display approximately "90" or more. If BCM display value is correct, replace BCM. If not, go to step 7).
  7. Turn ignition switch to "RUN" position, expose photocell to bright sunlight or a very bright incandescent light. Connect voltmeter between BCM White/Black wire connector and ground. Voltmeter should read one volt or less. If not, replace photocell. If voltage is okay, replace BCM.
  8. Cover photocell with cardboard. Connect voltmeter between BCM White/Black wire connector and ground. Voltmeter should read 4 volts or more. If not, replace photocell. If voltage is okay, replace BCM.
  1. Disconnect twilight headlight connector from interior relay center. Enter BCM diagnostics and select BCM output test BO05.
  2. Connect test light between Orange/Dark Blue (Black/Orange on Toronado) wire and ground. Test light should come on and BCM displays "HI" or "LO". If not, check low beam circuit breaker No. 21 and wires for open circuit.
  3. On Eldorado and Seville, connect test light between Orange/Dark Blue and Yellow wires. Test light should come on and BCM displays "HI" or "LO". If not, check Yellow wire for open circuit.
  4. On all models, connect test light between Orange wire and ground. Test light should come on and BCM displays "HI" or "LO". If not, check BCM fuse and Orange wire for open circuit.
  5. Connect test light between Orange and Black/Pink wires. If test light does not come on and BCM displays "LO", check Black/Pink wire for open circuit. If test light comes on and BCM displays "HI", check Black/Pink wire for short to ground.
  6. On Toronado, connect a fused jumper between Black/Orange and Tan wires. Headlights should come on. If not, check or repair Tan wire.
  7. On all models, if results from the previous steps were correct, replace twilight headlight relay.
  1. Disconnect twilight park light connector from interior relay center. Enter BCM diagnostics and select BCM output test BO05.
  2. Connect test light between Orange wire and ground. Test light should come on and BCM displays "HI" or "LO". If not, check or repair Orange wire.
  3. On Eldorado and Seville, connect test light between Orange and Dark Green wires. Test light should come on and BCM displays "HI" or "LO". If not, check taillights fuse No. 15 and Orange wire for open circuit.
  4. On all models, connect test light between Orange and Black/Pink wires. If test light does not come on and BCM displays "LO", check Black/Pink wire for open circuit. If test light comes on and BCM displays "HI", check Black/Pink wire for short to ground.
  5. On Toronado, connect a fused jumper between Orange and Brown wires. If park lights come on, check or repair Brown wire.
  6. On all models, if all results from the previous steps were correct, replace twilight park light relay.

Removal & Installation (Caprice)

Disconnect negative battery terminal. Remove dash top cover. Remove electrical connector from photocell. Pinch photocell retainer and lift photocell out by rotating retainer. To remove amplifier, remove glove box. Remove ashtray. Remove amplifier from behind right instrument panel support. To install, reverse removal procedure.

Removal & Installation (Bonneville)

Disconnect negative battery terminal. Remove windshield defroster nozzle grille. Remove photocell socket. To remove photocell from socket, turn photocell counterclockwise. To remove amplifier, remove instrument panel trim plate, filler and reinforcement. Remove lower left and right side sound absorbing panels. Remover amplifier from underneath dashboard. To install, reverse removal procedure.

Removal & Installation (Brougham, DeVille & Fleetwood)

Remove instrument panel top cover, photocell mounting bracket and electrical connector. Remove photocell. To remove amplifier, remove lower left sound absorbing panel. Remove amplifier module from air duct. Remove electrical connectors. To install, reverse removal procedure.

Removal & Installation (Delta 88 & Ninety-Eight)

Disconnect negative battery terminal. Remove lower right side sound absorbing panel. Remove glove box. Twist photocell socket 1/4 turn. Unplug photocell sensor from socket. To remove amplifier module, remove center and lower panel trim plates. Unplug electrical connector from module. Remove module retaining screws and unclip right side defrost duct. To install, reverse removal procedure.

Removal & Installation (Eldorado & Seville)

Remove windshield defroster grille. Remove photocell and electrical connector. To install, reverse removal procedure.

Removal & Installation (Electra)

Disconnect battery ground. Remove dash top cover. Disconnect electrical connector. Pinch photocell retainer and remove photocell by rotating retainer. Remove glove box shell. Remove ashtray. Remove amplifier retaining screws and amplifier. To install, reverse removal procedure.

Removal & Installation (Riviera)

  1. Disconnect battery ground. Remove glove box shell and lower right side sound absorbing panel retaining screws to gain access to lower trim panel screws. Remove center trim panel by pulling straight out.
  2. Remove right trim panel. Disconnect electrical connector and remove amplifier retaining screws and bolts. Disconnect photocell electrical connector. Pop up and rotate retainer. Remove photocell. To install, reverse removal procedure.

Removal & Installation (Toronado)

Disconnect negative battery terminal. Remove lower right sound absorbing panel. Remove 2 screws attaching amplifier to tie bar. Disconnect amplifier electrical connector. Remove amplifier. Remove left speaker grille. Remove photocell socket from speaker grille by rotating counterclockwise. Remove photocell by pulling out of socket. To install, reverse removal procedure.

WIRING DIAGRAMS

For wiring diagrams, refer to appropriate chassis wiring diagram in WIRING DIAGRAMS section.