Exterior Lighting

Exterior Lighting

The exterior lighting system consists of the following components:

- Headlamp assemblies
- Lighting Control Module (LCM) (located under the instrument panel rearward of the accelerator pedal)
- Stoplamp switch
- Headlamp switch
- Multifunction switch
- Light sensor
- High mounted stoplamp
- Rear lamp assemblies
- License plate lamps
- Police fuse/relay center(s) and wiring (if equipped)

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. 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

Headlamps

The headlamp system is a dual-beam pattern system. It consists of a low and high beam, with a replaceable bulb. The Lighting Control Module (LCM) supplies voltage to the headlamps when demanded on. The LCM is located behind the LH instrument panel lower insulator rearward of the accelerator pedal.

The LCM monitors the headlamp switch. If a fault is detected with the headlamp switch inputs, the LCM defaults the exterior lights on.

Autolamps

The autolamp system provides light sensitive automatic on/off control of the exterior lamps. The autolamp system keeps the exterior lamps on for a pre-selected period of time after the ignition switch is turned to the OFF position. The pre-selected time delay is adjustable up to approximately 3 minutes. To adjust the autolamps time delay, refer to Autolamps Time Delay Adjustment Autolamps Time Delay Adjustment.

Vehicles equipped with autolamps also have a feature that turns on the exterior lamps when the wipers are on. For diagnostics of the headlamps on with wipers on feature, refer to Wipers and Washers Testing and Inspection.

Stoplamps

The stoplamps are supplied voltage directly from the stoplamp switch when the brake pedal is applied.

Turn Signal/Hazard and Cornering Lamps

When the multifunction switch is placed in the LH or RH TURN position, the multifunction switch routes voltage to the LH or RH turn signal lamps. The LCM then cycles the voltage on and off approximately 80 times per minute. If a front or rear turn bulb is inoperative, the LCM cycles the voltage on and off approximately 160 times per minute.

The hazard flasher lamp switch is integral to the multifunction switch. When the hazard flasher lamp switch is engaged, the multifunction switch supplies voltage to all the turn lamps. The LCM cycles the voltage on and off approximately 80 times per minute.

When the multifunction switch is placed in the LH or RH TURN position and the parking lamps are on, the multifunction switch provides a ground for the cornering lamps.

Parking Lamps

The LCM supplies voltage to the parking lamps when demanded, such as when the parking lamp switch is in the PARKING LAMPS ON position or when the autolamps feature has requested the exterior lamps on.

Fog Lamps

The fog lamp switch is integral to the headlamp switch. When the fog lamp switch is engaged, voltage is routed to the fog lamp relay coil, which then energizes and routes voltage to the fog lamps. The fog lamps can be turned on when the ignition switch is in the RUN or ACC position, the parking lamps are on, and the high beam headlamps are off.

Reversing Lamps

When the transmission is placed in REVERSE (R), the digital Transmission Range (TR) sensor routes voltage to the reversing lamps.

Police Option

In addition to the previous listed components, a police option vehicle may include the following:

- Police glove compartment relay/fuse center
- Police luggage compartment relay/fuse center
- Package tray lamps
- Decklid flashing lamps
- Alternating flashing headlamps
- Rear deck LED flasher
- Strobe lamps

Daytime Running Lamps (DRL)

The Daytime Running Lamps (DRL) 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 high beams are illuminated at full intensity when flash-to-pass mode is requested.

The LCM can be configured to turn the DRL on for this vehicle. Refer to Module Configuration [1][2]Initial Inspection and Diagnostic Overview for information on this programmable parameter.