Exterior Lighting

EXTERIOR LIGHTING

NOTE: The smart junction box (SJB) is also known as the generic electronic module (GEM).

Headlamps
The headlamps are controlled by the SJB. The headlamp and multifunction switches are constantly monitored by the SJB. The SJB processes information (such as low beam, high beam or flash-to-pass requests) from the switch inputs, and then outputs voltage to the headlamps accordingly. In the event the SJB detects a fault with any of the headlamp switch inputs, all the exterior lamps are illuminated. There is also a headlamp battery saver feature. This feature turns off the headlamps 10 minutes after the ignition switch is turned OFF.

Headlamp Functionality - Halogen
When the low beams are requested (based on inputs to the SJB), the low beams are illuminated.

When the high beams are requested, the high beams are illuminated and the low beams turn off.

When the flash-to-pass feature is requested, the high beams are illuminated as long as the multifunction switch is held in the FLASH-TO-PASS position.

Headlamp Functionality - High Intensity Discharge (HID)
Vehicles equipped with HID headlamps utilize relays to control the voltage to the HID ballasts. The ballasts are located on the side of each headlamp assembly.

When the low beams are requested (based on inputs to the SJB), the HID relays are energized and the low beams are illuminated.

When the high beams are requested, the HID relays stay energized and a shutter within each headlamp is activated. This changes the headlamp beam pattern to illuminate a greater distance.

The flash-to-pass feature is unique for HID equipped vehicles. If the low beams are off when the flash-to-pass is requested, the HID relays and the shutters within the headlamps are activated for less than 0.5 second. If the low beams are on when the flash-to-pass is requested, the shutters within the headlamps are activated as long as the multifunction switch is held in the FLASH-TO-PASS position.

Stoplamps
The stoplamp outputs are controlled by the SJB. The stoplamp switch is monitored by the SJB. When the SJB detects the brake pedal is applied, the SJB processes this information and outputs voltage to the stoplamps.

Turn Signal and Hazard Lamps
All turn signal outputs are controlled by the SJB. The multifunction switch and the hazard switch are monitored by the SJB. When the multifunction switch is in the left or right turn position, or the hazard switch is engaged, the SJB processes this information and outputs on/off voltage to the appropriate turn signal and hazard lamps. All turn signal lamps provide a lamp outage indication.

Parking, Rear or License Plate Lamps
The parking, rear, license plate and side marker lamps are controlled by the SJB. The headlamp switch is monitored by the SJB. When the headlamp switch is in the HEADLAMPS ON or PARKING LAMPS ON position, the SJB processes this information and outputs voltage to the parking, rear, licence plate and side marker lamps.

The battery saver feature does not turn the parking lamps off when the headlamp switch is in the PARKING LAMPS ON position.

Fog Lamps
The fog lamps are controlled by the SJB. The SJB monitors inputs from the headlamp switch and the multifunction switch. The SJB can only turn the fog lamps on when the ignition switch is in the RUN position, the parking lamps are on and the high beams are off. When the fog lamp switch is engaged, the SJB then activates the fog lamp relay, providing power to the fog lamps.

Reversing Lamps
The reversing lamps are controlled by the SJB. The PCM sends a message through the communication network indicating the transmission is in REVERSE (R). The SJB processes this information and outputs voltage to the reversing lamps.

Daytime Running Lamps (DRL)
If the SJB is configured for DRL, this feature illuminates the low beam headlamps at a reduced intensity when the following conditions exist:
- The ignition switch is in the RUN position.
- The headlamp switch is in the OFF position.
- The parking brake is not engaged.