The exterior lighting system consist of the following lamps:

The headlamps may be turned on in 2 different ways. First, when the driver places the multifunction headlamp switch in the HDLP position, for normal operation. Second, with the headlamp switch placed in the OFF position for automatic lamp control (ALC) operation. During ALC operation, the headlamps will be off in daylight conditions however the flash to pass feature can be utilized. The ambient light sensor is a light sensitive transistor that varies its voltage signal to the body control module (BCM) in response to changes to the outside (ambient) light level. When the BCM receives a low light signal, it will turn on the headlights for ALC operation.

Battery positive voltage to the multifunction headlamp switch is supplied by the PARK LP fuse in the underhood fuse block. When the multifunction headlamp switch is in the HDLP position, the headlamp power relay coil which is grounded by G102, is energized. A voltage signal is also sent to the headlamp grounding relay coil which is grounded by G200. When the headlamp grounding relay is energized, a ground signal from G200 is sent to the body control module (BCM) signaling that the headlamp switch is activated. When the headlamp power relay is energized, the relay supplies battery voltage to the LT HDLP and RT HDLP fuses which supply voltage to all of the headlamps.

Both low beam headlamps are grounded through the flash to pass (FTP) relay in the normally closed position to G117. The IGN E fuse in the underhood fuse block supplies ignition positive voltage to the multifunction headlamp dimmer switch. When the multifunction headlamp dimmer switch is placed in the HI or FTP position, the ignition positive voltage signal will energize the flash to pass relay coil switching ground G117 from the low beam headlamps to the high beam headlamps. This action also sends the ground to the BCM signaling that the high beam headlamps have been activated.

Headlamp Leveling

Voltage is supplied to the headlamp leveling switch through the IGN E fuse in the underhood fuse block. The headlamp leveling actuators are also powered by the same fuse but from a different terminal location in the underhood fuse block than the headlamp leveling switch. The headlamp leveling switch varies the amount of current to the actuators causing them to move simultaneously up or down to each selected position. Ground for the actuators are supplied by G102 and the switch is supplied by G200.

With both the ignition switch in the RUN position, and the park lamps or low beam headlamps on, the fog lights and indicators will illuminate when the driver presses the fog lamp switch. The PARK LP fuse in the engine wiring harness junction block supplies battery positive voltage to the fog lamp relay for the fog lamp supply voltage 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 pressed, a ground signal from G200 is sent to the body control module (BCM) requesting to ground the fog lamp relay control circuit energizing the relay. The current flow is from the fog lamp relay to both front fog lamps and to grounds G111 and G112. The state of the fog lamps will remain the same until the fog lamp switch is pressed again, 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 the same way as the front except when the BCM senses that the high beam headlamps have been activated it will not turn off the rear fog lamps. The ground for the rear fog lamps is supplied by G450.

The tail, marker and license lamps are turned on when the multifunction headlamp switch is placed in the PKLP or HDLP position or anytime the headlights are requested. The PARK LP fuse in the engine wiring harness junction block supplies battery positive voltage to the park lamp relay coil and supply, multifunction headlamp switch and park lamp switch relay. The body control module (BCM) provides a ground, or control circuit, to the park lamp relay coil circuit during ALC operation. When the tail, marker and license lamps are turned on during ALC operation, the BCM grounds the park lamps relay coil energizing the park lamp relay. The tail, marker and license lamps can also be supplied battery positive voltage from the park lamp switch relay. When the headlamp switch is in the PKLP or HDLP position, the park lamp switch relay, utilizing ground G117, is energized. Current flow is to the FR PRK LPS fuse, LR PRK LPS fuse, RR PRK LPS fuse and the TRL PRK LPS fuse and to their respective tail, marker and license lamps. The front marker lamps are grounded at G111 and G112. The tail and rear marker lamps are grounded at G450. The license lamps are grounded at G402. If the multifunction headlamp switch is left in the ON position, the tail, marker and license lamps will remain on until turned off or the battery runs dead.

The HAZ SW fuse in the IP fuse block supplies battery positive voltage to the hazard warning switch. The TURN fuse in the IP fuse block supplies Ignition positive voltage to the hazard warning switch. The hazard warning switch is grounded at G200. With the ignition switch in the RUN or START position, ignition positive voltage is connected through the hazard warning switch to the multifunction turn signal switch. When the turn signal switch is placed in either the left or right position, the circuit is complete from the hazard warning switch through the multifunction turn signal switch to the activated turn signal lamps and to ground. The hazard warning switch then sends an on-off voltage signal to either the left or right turn signals and their instrument panel cluster (IPC) indicator. When the hazard switch is activated, all turn signal lamps will flash including both IPC turn indicators. The front turn signals are grounded at G112. The turn signal repeater lamps on each fender are grounded at G111. The rear turn signals are grounded at G450.

The STOP LP fuse in the engine wiring harness junction block supplies battery positive voltage to the normally open stop lamp switch. When the driver presses the brake pedal, the switch contacts close and battery positive voltage is supplied to both the VEH HMSL fuse and the TRL HMSL fuse. The current flow is now to the stop lamps, center high mounted stop lamp (CHMSL) and high mounted stop lamp resistor which are all grounded at G450.

The B/U LP fuse in the engine wiring harness junction block supplies battery positive voltage to the normally open backup lamp switch. When driver places the gear selector lever is in the REVERSE position, the backup lamp switch closes and the current flow is from the backup lamp switch through the VEH B/U fuse to the backup lamps. The backup lamps are grounded at G450.