Headlamp: Description and Operation

PRINCIPLES OF OPERATION

The autolamp system provides light-sensitive automatic on/off control of the headlamps and parking lamps controlled by the vehicle security module when the headlamp switch is in the autolamps position. When the ignition switch is turned to the RUN or START position with the autolamps feature already enabled and the ambient light level is dark, the vehicle security module will request the headlamps and parking lamps be turned on. When the autolamps are disabled, the vehicle security module will request the headlamps and parking lamps to be turned off, regardless of the ignition switch position. When the vehicle security module has turned on the exterior lamps and the ignition is turned to the OFF or ACCY position, the exterior lamps will remain on for an additional time specified by the customer or the headlamp switch is turned off.

When the autolamps have been enabled and the ignition switch is in the RUN/START position, the vehicle security module will request that the exterior lamps be turned on or off based on ambient light level. If the vehicle enters darkness for at least 15 seconds, the vehicle security module will request the exterior lamps on. If the vehicle enters light for at least 15 seconds, the vehicle security module will request the exterior lamps off. By delaying turning on and off the exterior lamps during short periods of darkness and light, the vehicle security module prevents the exterior lamps from flashing on and off.