Exterior Lighting - System Operation and Component Description

The BCM supplies a high current switched voltage to the headlamp assemblies to supply the necessary current to operate the ballast and lamps.

High Intensity Discharge (HID) headlamps utilize a ballast, mounted to each headlamp assembly, to provide the necessary voltage to illuminate the High Intensity Discharge (HID) bulbs.

The BCM also provides an Field Effect Transistor (FET) protection of the exterior lamps switched voltage and low beam output circuits. When an excessive current draw is detected, the BCM disables the affected circuit driver.

Refer to: Module Controlled Functions - System Operation and Component Description (419-10 Multifunction Electronic Modules, Description and Operation).

High Beams

The SCCM monitors the LH steering column multifunction switch for a high beam request. When the LH steering column multifunction switch is in the HIGH BEAMS position, the SCCM sends a message over the HS-CAN2 to the GWM then the GWM sends the message to the BCM over the HS-CAN1.

When the low beams are on and the BCM receives a request for high beams, the High Intensity Discharge (HID) bulbs remains powered on and the shutter within each headlamp are activated. This changes the headlamp beam pattern to illuminate a greater distance.

The BCM supplies a high current switched voltage to the headlamp assemblies to supply the necessary current to operate the high beam shutters.

The BCM also provides an Field Effect Transistor (FET) protection of the exterior lamps switched voltage and high beam output circuits. When an excessive current draw is detected, the BCM disables the affected circuit driver.

Refer to: Module Controlled Functions - System Operation and Component Description (419-10 Multifunction Electronic Modules, Description and Operation).

Flash-To-Pass

The SCCM monitors the LH steering column multifunction switch for a flash-to-pass request. When the LH steering column multifunction switch is in the FLASH-TO-PASS position, the SCCM sends a message over the HS-CAN2 to the GWM then the GWM sends the message to the BCM over the HS-CAN1.

When the ignition is in RUN and the flash-to-pass is requested, the high beams are activated as long as the LH steering column multifunction switch is held in the flash-to-pass position.

Headlamp Exit Delay

When the ignition is OFF and the LH steering column multifunction switch is placed in the FLASH-TO-PASS position and released, the parking lamps and low beams are illuminated. They remain illuminated until:

3 minutes have elapsed with a door open. 30 seconds have elapsed after all doors are closed. the LH steering column multifunction switch is placed in the flash-to-pass position again. the ignition switches to RUN.

Within the 30 second delay and all the doors closed, opening any door results in the 3 minute timer restarting.

Headlamps - China Only

System Diagram