Fog/Driving Lamp: Description and Operation

The fog lamp switch is a direct input to the BCM. The BCM sends a PCI data bus message to the IPM informing it to turn on the fog lamps. This circuit is electronically controlled and continuously monitored for malfunctions. Fog lamp functionality is not equipped on all vehicles. The IPM "learns" that the vehicle is equipped with fog lamps by reading the BCM data bus message. The Fog lamps can only be ON when the park and low beams are ON. If the high beams are switched ON then the Fog lamps will be automatically turned OFF.