Exterior Lighting

Exterior Lighting

The exterior lighting system consists of the following components:

- Headlamp assemblies
- Rear lamp assemblies
- Reversing lamps
- License plate lamp
- Front turn signal/cornering lamps
- High mounted stoplamp
- Light sensor (located under the center of the defroster grille panel)
- Multifunction switch
- Headlamp switch
- Stoplamp switch
- Ballast (HID headlamps only) (located in the headlamp assembly)
- Lighting Control Module (LCM) (located behind the LH instrument panel lower insulator rearward of the accelerator pedal)

Lamp Assembly Condensation

Exterior lamps are vented to accommodate normal changes in pressure. Condensation can be a natural by-product of this design. When moist air enters the lamp assembly through the vents, there is a possibility that condensation can occur if the temperature is cold. When normal condensation occurs, a thin film of mist can form on the interior of the lens. The thin mist eventually clears and exits through the vents during normal operation. Time to clear the lens of acceptable mist varies with ambient humidity and lamp types. Normal condensation clears from any lamp in 48 hours under dry conditions.

Do NOT replace a lamp assembly with acceptable levels of condensation such as:

- presence of thin mist (no streaks, drip marks or droplets are present)
- fine mist covers less than 50% of the lens

Examples of unacceptable moisture (usually caused by a lamp housing leak):

- water puddling inside the lamp
- large water droplets, drip marks or streaks present on the interior of the lens

Lighting Control Module (LCM)

The LCM is a microprocessor based module that controls several vehicle subsystems. It responds to electrical input signals from various switches, sensors, and external modules.

The LCM exterior lighting subsystem functions include:

- Headlamps with autolamps
- Turn signal lamps/hazard flasher lamps
- Parking lamps
- Battery saver

The LCM also has a feature that turns on the exterior lamps when the windshield wipers are turned on. For diagnostics or description and operation, refer to Wiper and Washer Systems.

Daytime Running Lamps (DRL)

The Daytime Running Lamps (DRL) system is controlled by the LCM. The system is designed to turn the high beam headlamps ON at a reduced intensity when the following conditions are met:

- The ignition switch is in the RUN position.
- The headlamps have not been commanded on from any other input.
- The vehicle is not in PARK (P).

The DRL system remains active until the autolamp system turns on the headlamps or the headlamp switch is turned to the HEADLAMPS ON position.

The LCM can be configured to turn the DRL on for this vehicle. Refer to Information Bus for information on this programmable parameter.