Fog Lamps

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

With the ignition switch in the ON position, and the park lamps or low beam headlights on, the fog lights will illuminate when the driver presses the fog lamp switch. The FOG LPS fuse in the underhood fuse block, supplies battery positive voltage to both the fog lamp relay switch contacts and the fog lamp relay coil circuit. The fog lamp relay coil is controlled by the body control module (BCM). When the fog lamp switch is pressed, the BCM fog lamp switch input is grounded. The BCM will then energize the fog lamp relay coil control circuit. The current flow is now from the fog lamp relay to both front fog lamps and to ground G100 and G101. The state of the fog lamps either ON or OFF will remain the same until the front fog lamp switch is pressed again, or the ignition switch is cycled OFF and ON. The park lamps or low beam headlights must be ON in order for the fog lights to be illuminated. Fog lamp operation will be cancelled whenever the park lamps, are turned OFF or the high beam headlights have been selected.