Fog/Driving Lamp: Description and Operation

Pressing the fog lamp switch button will turn the fog lamps ON, as long as the headlamp switch is NOT in the OFF position. When the fog lamps are ON, an indicator on the fog lamp switch will illuminate. Pressing the switch again will turn the fog lamps OFF. The FOG relay in the underhood fuse block controls the fog lamps. The switched side of the relay receives battery voltage at all times from the FRT Park FOG LPS Fuse. The coil side feed circuit of the fog lamp relay receives voltage from the HDLP fuses via an inactive high beam headlamp (the voltage will be pulled low with the high beams ON disabling the fog lamps). The body control module (BCM) will provide an enable signal to the fog lamp switch when the ignition is ON and the headlamp switch is in PARK or HEAD position. With the fog lamp enable circuit active and the fog lamp switch is pressed, a ground is applied to the fog lamp relay control circuit. This energizes the relay, closing the switched contact and applying battery voltage to the fog lamps turning them on. The fog lamps receive a constant ground from G101.