DESCRIPTION
The Firebird headlight light monitor is electrically operated. It consists of headlight dimmer switch and a light monitoring module. Headlight dimmer switch is located behind instrument panel on left upper side of steering column. Light monitoring module is located behind instrument panel, at base of steering column.
CIRCUIT OPERATION
Voltage is supplied to the headlight switch through the headlight circuit breaker. When the switch is in "HEAD" position, current is supplied through the Yellow wire to the headlight dimmer switch. With dimmer switch in "LO" position, current is supplied through the matched Tan and Black resistance wires to light monitoring module, and to left and right low beam head lights, lighting headlights.
With the dimmer switch in "HI" position, voltage is supplied through the Lt. Green wire, and matched resistance wires to light monitoring module, and to left and right high beam headlights, lighting headlights. If headlight is burned out, the beam comparator detects the open in lighting filament and fault is displayed at Driver Information Center (DIC).
PRELIMINARY CHECK
If one headlight is dim, check ground on that side. If high beams do not light, but "HI BEAM" indicator lights, check Light Green wire for open. If one headlight does not work, check connections, headlight, and wires to headlight. If headlights do not turn off, replace headlight switch.
SYMPTOM DIAGNOSIS
If all headlights are inoperative or intermittent, go to LIGHT SWITCH TEST. If high/low beams on both sides do not operate, or "HIGH BEAM" indicator does not operate, go to DIMMER SWITCH TEST.
Light Switch Test
- Set light switch to "HEAD" position. Connect test light at light switch connector Red wire and ground. If test light does not operate, check fusible link and Red wire for open. Using same test light, check continuity between Yellow wire and ground. If test light does not operate, go to next step. If test light operates for either test, go to DIMMER SWITCH TEST.
- Set dimmer switch to "LO" position. Connect 15-amp fused jumper between disconnected light switch connector Red and Yellow wire. If headlights operate, replace light switch. Put dimmer switch in "HI" position and perform same test.l If high beams operate, replace light switch. If headlights or high beams do not operate, replace light switch. If headlights or high beams do not operate in either test, check for short to ground in head light wiring.
Dimmer Switch Test
- Set light switch to "HEAD" and dimmer switch to "LO" positions. Using test light, check continuity between Yellow wire and ground. If test light does not operate, check Yellow wire for open. If test light operates, check wiring for open.
- Be sure light switch and dimmer switch and dimmer switch are still in "HEAD" and "LO" positions. Using test light check continuity between Tan wire and ground. If test light does not operate, replace dimmer switch. If test light operates, check wiring for open.
- Set dimmer switch in "HI" position. Using test light, check continuity between Light Green wire and ground. If test light does not operate, replace dimmer switch. If test light operates, check wiring for open.