Exterior Lighting

LAMPS/LIGHTING - EXTERIOR
The exterior lighting system for this model include the following components:
- Backup Lamps
- Brake Lamps
- Daytime Running Lamps
- Front Fog Lamps
- Hazard Warning Lamps
- Headlamps
- Park Lamps
- Turn Signal Lamps

Other components of the exterior lighting system for this model include:
- Backup Lamp Switch
- Brake Lamp Switch
- Front Control Module
- Front Fog Lamp Relay
- Hazard Switch
- Multi-Function Switch
- Park Lamp Relay
- Trailer Tow Connectors

Some of the interior and exterior lighting functions are governed by the front control module. The headlamp, dome, and door ajar switches provide signals to the instrument cluster. The instrument cluster sends a J1850 message to the front control module to enable the necessary components for illumination. Hard wired circuitry connects the exterior lighting system components to the electrical system of the vehicle. Refer to the appropriate wiring information.

DAYTIME RUNNING LAMPS
Power is reduced using pulse-width modulation to the high beams, where by the power is switched on and off rapidly instead of remaining on continuously. The duration and interval of the power pulses is programmed into the Front Control Module (FCM).

HEADLAMP SYSTEM
The instrument cluster monitors both the multiplexed headlamp and multifunction switches. The instrument cluster transmits a J1850 bus message to the front control module (FCM) to activate the headlamps. The headlamp system will default to headlamps ON position when ignition switch is ON and when an open or short circuit failure occurs on the headlamp switch input to the instrument cluster. The system will return to normal operation when the open or short is repaired. A fault will be reported by the Instrument Cluster when a failure occurs on the dimmer or headlamp switch input.

If the exterior lamps are ON, and the headlamp switch is in any position other than OFF, with the ignition switch OFF (LOCK) after 5 minutes, the Instrument Cluster transmits a message via J1850 informing the the FCM. The FCM will then turn off the headlamps, park lamps and fog lamps. This feature (load shed) prevents the vehicle battery from being discharged when the vehicle lights have been left ON.

HEADLAMP TIME DELAY SYSTEM
The headlamp time delay system is activated by turning the headlamps ON (high or low beam) while the engine is running, turning the ignition switch OFF, and then turning the headlamp switch OFF within 45 seconds. The system will not activate if more than 45 seconds elapse between ignition switch OFF and headlamp switch OFF. The FCM will allow the headlamps to remain ON for 60 seconds (configurable) before they automatically turn off (If the key is in the ignition during the headlamp time delay mode, then the headlamps including panel dimming will be ON).

LAMP OUTAGE
If one or more of the following lamps (Low and/or High beams, Brake and/or Turn Signal) are out, then a "lamps out" indicator located in the cluster will illuminate.

OPTICAL HORN/HIGH BEAMS
When the multiplexed multifunction switch is pulled to the first detent (optical horn) signal, the headlamps are ON, the Instrument Cluster shall send a message via J1850 to the FCM to turn on the headlamps drivers to illuminate all four filaments (Low and High beams). When the multifunction switch is pulled to the second detent (high beam) signal and the headlamps are ON, the Instrument Cluster shall send a message via J1850 to the FCM to turn on the headlamps drivers. The High Beams are illuminated and the Low Beams and Fog Lamps (if ON) are extinguished. If the headlamps were in the high beam configuration when power was removed from the headlamps, the headlamps will return to their last state prior to being shut off.