System Operation

Headlamps

System Operation

System Diagram





Low Beams

The headlamp switch sends a status message over the LIN (Local Interconnect Network) circuit to the BCM (Body Control Module) to indicate the headlamp switch status (position or a fault within the headlamp switch).

If the BCM (Body Control Module) detects a fault from (or loses communication with) the headlamp switch, the BCM (Body Control Module) turns the parking lamps and headlamps on. If this situation occurs, the BCM (Body Control Module) cannot be ruled immediately as being at fault. This is normal behavior of the BCM (Body Control Module) design as a fault has been detected with the inputs from the headlamp switch.

When the BCM (Body Control Module) receives an input requesting the headlamps on, it supplies voltage to the headlamp bulbs within each headlamp assembly.

Vehicles with halogen headlamps use single filament bulbs.

High Beams

The SASM (Steering Angle Sensor Module) monitors the multifunction switch for a high beam request. When the multifunction switch is in the high beam position, the SASM (Steering Angle Sensor Module) sends a message to the BCM (Body Control Module) over the LIN (Local Interconnect Network) circuit indicating the request.

When the low beams are on and the BCM (Body Control Module) receives a request for high beams, the headlamps remain powered and the high beams are activated. This adds light and changes the headlamp beam pattern to illuminate a greater distance.

Flash-To-Pass

The SASM (Steering Angle Sensor Module) monitors the multifunction switch for a flash-to-pass request. When the multifunction switch is in the flash-to-pass position, the SASM (Steering Angle Sensor Module) sends a message to the BCM (Body Control Module) over the LIN (Local Interconnect Network) circuit indicating the request.

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

Headlamp Exit Delay

When the ignition is off and the 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 multifunction switch is placed in the flash-to-pass position again, or

- 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.