GM Service Manual Online
For 1990-2009 cars only

Park and License Lamps

The park and license lamps are controlled by the PARK LAMP relay in the RH I/P accessory wiring junction block. Both the coil and the switched sides of the relay receive B+ at all times. When the headlamp switch is turned to the PARK position, ground is supplied through the headlamp switch to the BCM through the park lamp switch input circuit. The BCM then applies a ground through the park lamp relay coil control circuit to the PARK LAMP relay. This energizes the relay, closing the switch contact and applies B+ to both the REAR PARK LAMP fuse and the FRONT PARK LAMP fuse. B+ is then applied through the park lamps ON circuit to the front and rear park lamps and the license lamps turning them on. The park lamps and license lamps receive ground at all times.

Turn Lamps

When the ignition is turned to the ON position, B+ is supplied to the TURN SIGNAL fuse. B+ is then applied through the turn signal fuse circuit to the hazard lamp/turn signal flasher. From the flasher the turn signal switch output circuit is applied to the turn signal switch. From the turn signal switch, the turn signal is applied to the instrument panel cluster for turn indicator and to all of the turn lamps flashing the lamps on and off. The turn lamps receive ground at all times.

Hazard Lamps

The hazard lamps receive B+ at all times through the HAZARD SWITCH fuse to the hazard lamp/turn signal flasher. When the hazard switch is placed in the HAZARD position, B+ is applied to all of the turn lamps and turn indicators simultaneously flashing them on and off.

Stop Lamps

The stop lamps receive B+ at all times through the BRAKE SWITCH fuse to the stop lamp switch. When the stop lamp switch is closed, B+ is applied to the stop lamp switch output circuit to all the stop lamps turning them on. The stop lamps receive ground at all times.