Headlamps

HEADLAMPS
The headlamp system includes the SCM, the EMIC, the FCM, 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 ground screws to the front end sheet metal within the engine compartment.

The SCM monitors a hard wired multiplex input to determine the state of the left multi-function switch and whether the headlamp high or low beams are selected. The SCM then sends the appropriate electronic headlamp switch and headlamp beam select switch status messages to the FCM over the CAN data bus. The FCM responds to these messages by providing a pulse width modulated voltage output to the proper headlamp bulbs through the right and left low and high beam feed circuits to illuminate the selected headlamp beams. The FCM also sends the appropriate electronic messages to the EMIC to control the illumination of the high beam indicator.

The FCM also 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. The FCM 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 Lock position. The SCM provides a fail-safe feature for the headlamps, which will send an electronic message to the FCM to turn the low beam headlamps On automatically if the SCM detects no input from the left multi-function switch. The FCM also provides a fail-safe feature for the headlamps that will turn the headlamps On automatically whenever a loss of CAN bus communication is detected with the ignition switch in the On position.

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