Section 18 (Lamps/Lighting - Exterior (Service Information) 500 - Electric): Operation: Headlamps

The headlamp system includes the BCM, the IPC and the left (lighting) multi-function switch on the steering column. The headlamp bulbs have a path to ground at all times through their connection to the headlamp and dash wire harness. The headlamp and dash wire harness has takeouts with eyelet terminals that are secured by screws to the front end sheet metal within the engine compartment. The BCM monitors hard wired inputs to determine the status of the left multi-function switch and whether the headlamp high or low beams are selected. The BCM then controls headlamp illumination through relays soldered onto the BCM internal circuit board.

When the BCM detects a change in headlamp beam selection, the BCM energizes or de-energizes a high side driver, which controls an output to the solenoid that operates the shutter in each headlamp. The BCM also sends the appropriate electronic messages to the IPC to control the illumination of the high beam indicator. The BCM remembers which beams (LOW or HIGH) were selected when the headlamps were last turned OFF, and energizes those beams again the next time the headlamps are turned ON.

Each headlamp includes an integral reflector adjustment screw to be used for static aiming of the headlamps.