Headlights - Automatic Twilight Sentinel Buick Roadmaster VIII

DESCRIPTION

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

The system operates independently of the headlight switch. On models equipped with Daytime Running Lights (DRL), the twilight sentinel system controls both systems automatically. Twilight sentinel system operates when headlight switch is in OFF position, but ignition and twilight sentinel switches must be in ON position. Headlight switch operates exterior lights independently of twilight sentinel system.

OPERATION

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

Twilight sentinel system provides a 30-second delay before switching lights on or off, thus preventing system from operating under sudden ambient lighting changes, such as passing through tunnels and exposure to bright lights at night.

AIR BAG PRECAUTIONS

Observe following precautions when working on vehicles equipped with Supplemental Inflatable Restraint (SIR) air bag systems

1. Before performing any instrument panel testing, diagnosis, or repair, disable SIR system by disconnecting negative battery cable and Yellow 2-pin connector at base of steering column.
2. To enable SIR system to power down, wait 20 minutes before making any repairs. System back-up power supply still retains enough voltage to deploy air bag for a short time after battery is disconnected.
3. To avoid accidental air bag deployment, avoid Yellow SIR wiring harnesses when trouble shooting, repairing, or replacing instrument panel components. All SIR wiring harnesses are Yellow.

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 using fingers or metal tools. When unplugging connectors, never 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.

Components Possibly Damaged By ESD

1. ABS Controller.
2. Central Control Module (CCM).
3. Chime Module And Cruise Control Module.
4. Distributorless Ignition System (DIS) Module.
5. Electronic Instrument Cluster Panel (IPC).
6. Electronic Control Module (ECM) (Including PROM, CAL-PAK, Or MEM-CAL).
7. HVAC Electronic A/C-Heater Controllers And Modules.
8. Power Control Module (PCM).
9. Radio And Theft Deterrent Modules.
10. Twilight Sentinel Module Or Amplifier.

Lights Do Not Turn On In Darkness

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

Lights Do Not Turn Off In Daylight

Inoperative photocell or amplifier. Poor contact between photocell and socket, or socket disengaged from mounting hole. Obstructed photocell.

Lights Do Not Turn Off After Ignition Is Off

Fuse blown. Inoperative time delay control. Open wiring. Inoperative amplifier. Malfunctioning photocell.

Lights Do Not Stay On Proper Time Span After Ignition Is Off

Inoperative time delay control. High resistance at amplifier connector. Short in wiring. Inoperative amplifier.

Warning Chime Does Not Operate

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

TESTING

TWILIGHT SENTINEL SYSTEM OPERATION TEST

Note. Twilight sentinel lighting system should work properly when manually operated under following conditions: twilight sentinel control is in ON position (between MIN and MAX), headlight switch is in OFF position, and photocell is uncovered. Before testing, check all fuses for continuity.

Note. Unless otherwise specified, make all measurements using a digital volt-ohmmeter with an input impedance of 10 megohms.

Without DRL

1. Turn headlights off. Turn ignition on. Set twilight sentinel control to mid position. Cover photocell on top of instrument panel using cardboard. All exterior lighting should come on within 30 seconds.
2. Uncover photocell. Expose photocell to sunlight or bright incandescent light. All exterior lights should turn off within 30 seconds.
3. Again cover photocell using cardboard. Wait until exterior lights come on, then turn ignition off. All exterior lights should turn off after a few minutes delay. Delay depends on position of twilight sentinel switch. With switch in MAX position, lights could remain on for about 3-4 minutes. If system performs as described, twilight sentinel system is operating properly. If system does not perform as described, see appropriate TEST PROCEDURE.

With DRL

1. Turn headlights off. Turn ignition on. Set twilight sentinel switch to mid position. Cover photocell on top of instrument panel using cardboard. All exterior lights should come on within 30 seconds.
2. Uncover photocell. Expose photocell to sunlight or bright incandescent light. All exterior lights should turn off within 30 seconds.
3. Again cover photocell using cardboard. Wait until exterior lights come on, then turn ignition off. All exterior lights should turn off after a few minutes delay. Delay depends on twilight sentinel switch position. With switch in MAX position, lighting could remain on for about 4 minutes.
4. Turn ignition on. Set twilight sentinel control to MIN position. Expose photocell to sunlight or bright incandescent light. Move gear selector lever out of Park position. Body lights should come on, together with headlights at reduced intensity. Set gear selector lever to Park position. Body lights should remain on, but headlights should turn off. If lights operate as specified, system is operating properly. If system does not perform as described, see appropriate TEST PROCEDURE.

EXTERIOR LIGHTS ARE ON DURING DAYLIGHT - TEST PROCEDURE

1. Turn twilight sentinel on. Turn ignition on. Remove photocell light sensor. See «TWILIGHT SENTINEL PHOTOCELL»(/buick/roadmaster/viii-1991-1996/remont/headlights/#headlights-automatic-twilight-sentinel) under REMOVAL & INSTALLATION.
2. Connect fused jumper wire between both photocell sensor connector terminals (Light Green/Black and Yellow/Black wires). If headlights are not on, replace photocell sensor. If headlights are on, go to next step.
3. Check for open in Light Green/Black or Yellow wire, or for poor connections at photocell or module. Locate Twilight Sentinel/Daytime Running Lights (TS/DRL) module, above and to right rear of steering column support bracket. Check for poor connections at module Blue C1 connector terminals "G" (Light Green/Black wire) and "H" (Yellow wire). If wires and connections are good, replace twilight sentinel/daytime running lights module.

TWILIGHT SENTINEL TURNS ON HEADLIGHTS ONLY - TEST PROCEDURE

1. Locate twilight sentinel module, above and to right rear of steering column support bracket. Using test light, backprobe twilight sentinel module Black C2 connector terminal "A" (Orange wire). (Scheme 1)or (Scheme 2). If battery voltage exists, go to next step. If battery voltage does not exist, check for open in Orange wire between twilight sentinel module and fuse No. 14.
2. Turn ignition on. Turn twilight sentinel on. Cover photocell on top of instrument panel. Backprobe twilight sentinel module Black C2 connector terminal "H" (Brown wire). If battery voltage exists, repair open in Brown wire from twilight sentinel module to body lights. If battery voltage does not exist, check Brown wire for poor connection at module. If connection is good, replace twilight sentinel module.

Scheme 1

Scheme 2

TWILIGHT SENTINEL TURNS ON BODY LIGHTS ONLY - TEST PROCEDURES

1. Turn twilight sentinel on. Turn ignition on. Cover photocell on top of instrument panel. Locate twilight sentinel module, above and to right rear of steering column support bracket.
2. Backprobe twilight sentinel module Black C2 connector, terminal "F" (Yellow wire). If battery voltage exists, repair open in Yellow wire between twilight sentinel module and dimmer switch.
3. If battery voltage does not exist, check for poor connection of Yellow wire at module connector. If connection is good, replace twilight sentinel module.

TWILIGHT SENTINEL DOES NOT OPERATE; HEADLIGHT SWITCH OPERATES NORMALLY - TEST PROCEDURE

1. Turn headlights off. Locate twilight sentinel module, above and to right of steering column support bracket. Backprobe twilight sentinel module Black C2 connector terminal "D" (Dark Green/White wire). If battery voltage exists, go to next step. If battery voltage does not exist, go to step 11).
2. Turn ignition on. Backprobe twilight sentinel module Blue C1 connector, terminal "E" (Pink/Black wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair open in Pink/Black wire between twilight sentinel module and fuse No. 17.
3. Connect test light between module Blue C1 connector terminals "D" (Black wire) and "E" (Pink/Black wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair open in Black wire to ground.
4. Turn twilight sentinel off. Measure voltage at Blue C1 connector terminal "A" (Light Green wire). If battery voltage exists, go to next step. If battery voltage does not exist, check for poor connection at terminal "A". If connection is okay, replace twilight sentinel module.
5. Measure voltage at twilight sentinel switch terminal "B" (Light Green wire). If battery voltage exists, go to next step. If battery voltage does not exist, check for open circuit in Light Green wire from twilight sentinel module to switch.
6. Using test light, backprobe between twilight sentinel switch terminals "B" (Light Green wire) and "C" (Black wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair Black wire from terminal "C" to ground.
7. Unplug photocell sensor. If headlights and body lights are not on, go to next step. If headlights and body lights are on, replace photocell sensor.
8. Measure voltage at photocell connector Light Green/Black wire. If battery voltage does not exist, go to next step. If battery voltage exists, check Light Green/Black wire for short to voltage. If wire is okay, replace twilight sentinel module.
9. Check Light Green/Black wire between photocell sensor and twilight sensor module. If wire is okay, measure voltage between Light Green/Black and Yellow/Black wires at photocell sensor connector. If battery voltage exists, go to next step. If battery voltage does not exist, check Yellow/Black wire. If wire is okay, replace twilight sentinel module.
10. Check for poor connections at twilight sentinel switch. If connections are okay, replace switch.
11. Using test light, backprobe headlight switch terminal "B" (Dark Green/White wire). If battery voltage exists, check switch connections. If connections are okay, replace switch. If battery voltage does not exist, check for open circuit in Dark Green/White wire between switch and twilight sentinel module.

HEADLIGHT DELAY INOPERATIVE - TEST PROCEDURE

1. Turn ignition on. Turn twilight sentinel on. Turn headlights off. Using DVOM, backprobe twilight sentinel switch connector terminals "A" (Purple wire) and "D" (Black wire).
2. Observe meter while moving twilight sentinel delay control slowly from MIN to MAX position. If voltage does not exist, go to step 3). If voltage varies between battery voltage and 4 volts, replace twilight sentinel module. If battery voltage exists but does not change, check for poor connection at terminal "D" (Black wire) of twilight sentinel switch. If Black wire terminal connection is good, replace twilight sentinel switch.
3. Locate twilight sentinel module, above and to right of steering column support bracket. Using DVOM, backprobe twilight sentinel module Blue C1 connector, terminal "F" (Purple wire). If battery voltage does not exist, check for poor connection at Purple wire terminal to twilight sentinel switch connector. If connection is good, replace twilight sentinel switch. If battery voltage exists, repair open in Purple wire between twilight sentinel switch and module.

REMOVAL & INSTALLATION

Disconnect negative battery cable. Remove steering column lower cover. Remove steering column bolts. Lower steering wheel/column assembly to seat. Remove instrument panel face plate. Remove headlight switch module. Unplug connectors. To install, reverse removal procedure.

Disconnect negative battery cable. Remove lower trim panel under steering column. Locate amplifier, directly to right of steering column support bracket, at upper brace. Unplug connectors. Remove amplifier by sliding from bracket. To install, reverse removal procedure.

Depending on model, photocell is either mounted under left defroster grille or secured to top of instrument panel. Unsnap defroster grille. Twist photocell counterclockwise to disengage photocell and socket. Unplug connector. To install, reverse removal procedure.

Wiring Diagram. Scheme 3

See also:
• TWILIGHT SENTINEL PHOTOCELL