Fog Lamps

WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

With both the ignition switch in the [RUN] position, and the park lamps ON, the fog lights will illuminate when the driver places the fog lamp switch in the ON position. The FOG LPS 15 A fuse in the engine wiring harness junction block supplies battery positive voltage to the fog lamp relay switch circuit. The park lamp relay supplies battery positive voltage to the fog lamp relay coil. With the headlamp switch in either the park or headlamp position, and the fog lamp switch is paced in the ON position, the body control module (BCM) will energize the fog lamp relay control circuit. The BCM receive: the park lamp ON signal from the interior park lamps supply voltage signal circuit. The current flow is from the fog lamp relay to both front fog lamps and to ground G100. The state of the fog lamps will remain the same until the fog lamp switch position is changed, or the ignition switch is cycled OFF and ON. Fog lamp operation will be cancelled whenever the park lamps, are turned OFF or the high beam headlights have been selected.

The rear fog lamps are controlled in much the same way, however the front fog lamps must be on in order to turn on the rear fog lamps. The rear fog lamps have there own relay, and both the relay control and current flow are the same as the front fog lamps.