Headlamps

HEADLAMPS
The headlamp system includes the Body Control Module (BCM), a low beam relay installed in the Junction Block (JB), a high beam relay installed in the JB (except Canada), a solid state Daytime Running Lamps (DRL) relay installed in the JB (Canada only), the exterior lighting switches integral to the left (lighting) control stalk of the multifunction switch, and the ElectroMechanical Instrument Cluster (EMIC). The headlamps have a path to ground at all times through the grille opening reinforcement wire harness and two take outs with eyelet terminals of the headlamp and dash wire harness that are secured by ground screws to the left inner fender shield in the engine compartment.

The BCM controls headlamp operation by monitoring the exterior lighting switch inputs from the multi-function switch, then energizing or de-energizing the low beam relay, the high beam relay or the solid state circuitry of the DRL relay. It also sends electronic messages to the EMIC over the Programmable Communications Interface (PCI) data bus to control operation of the high beam indicator. When each respective relay is energized, it provides battery voltage from a fuse in the Power Distribution Center (PDC) through a relay (low beam, high beam, or DRL) output circuit.

The BCM also provides a battery saver (load shedding) feature for the headlamps, which will turn these lamps off if they are left on for more than about eight minutes with the ignition switch in the Off position; and, a headlamp delay feature with optional delay intervals that can be programmed using a diagnostic scan tool. Each headlamp includes an integral reflector adjustment screw to be used for static aiming of the headlamp beams.