Rear

REAR FOG LAMPS
Rear fog lamps are installed on vehicles manufactured for certain markets where they are required. The rear fog lamp system includes a rear fog lamp relay installed in the Integrated Power Module (IPM), and a rear fog lamp switch integral to the left (lighting) multi-function switch on the steering column. The rear fog lamps have a path to ground at all times through their connection to the rear fascia wire harness. The SCM monitors a hard wired multiplex input from the left multi-function switch to determine whether the rear fog lamps are selected, then sends electronic rear fog lamp switch status messages to the FCM over the CAN data bus.

When the FCM receives a rear fog lamp request message it then controls rear fog lamp operation by energizing or de-energizing the rear fog lamp relay control coil. The FCM also sends the appropriate electronic message to the EMIC to illuminate or extinguish the rear fog lamp indicator. When the rear fog lamp relay is energized, it provides battery voltage from a fused B(+) fuse in the IPM to the rear fog lamps through the rear fog lamp relay output circuit. The FCM will automatically de-energize the rear fog lamps relay any time the front fog lamps are deselected. The FCM also provides a battery saver (load shedding) feature for the rear 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.

On vehicles with a factory-installed trailer towing package including the Trailer Tow Module (TTM), the FCM will suppress operation of the rear fog lamps on the vehicle whenever a trailer is connected, while the TTM operates the rear fog lamps on the trailer.