Front Fog Lamps

The front fog lamps have a path to ground at all times through their connection to the engine compartment wire harness. The engine compartment wire harness has takeouts with eyelet terminals that are secured by nuts to ground studs on the front end sheet metal within the engine compartment. The BCM monitors a hardwired multiplex input from the headlamp switch to determine whether the fog lamps are selected.

When the BCM receives a front fog lamp request  message it then controls front fog lamp operation by controlling a battery voltage output through high side drivers on right and left fog lamp feed circuits. The BCM also sends the appropriate electronic message to the IPC to illuminate or extinguish the front fog lamp indicator. In certain markets where required, the BCM will automatically de-energize the front fog lamps any time the headlamp high beams are selected.

The BCM also provides a battery saver (load shedding) feature for the front fog lamps, which will turn these lamps OFF if they are left ON for more than about eight minutes with the ignition switch in the LOCK position, if there is a charging system failure, or if the electrical system voltage falls below about 11.75 volts for more than about 30 seconds. The BCM will return the front fog lamps to normal operation when it detects that system voltage is greater than 13.0 volts for more than about 30 seconds.

Each front fog lamp includes an integral adjustment screw to be used for static aiming of the fog lamp beams.