Exterior Lighting - System Operation and Component Description: Autolamps

System Diagram 

Courtesy of FORD MOTOR COMPANY

Autolamps 

The BCM monitors the light sensor with a voltage signal. The light sensor input to the BCM varies with the ambient light conditions.

The headlamp switch sends a status message over the LIN circuit to the BCM to indicate the headlamp switch status (position or a fault within the headlamp switch).

When the BCM receives a headlamp switch status message from the headlamp switch indicating a request for the autolamps, the BCM monitors the light sensor for the ambient light condition. If the BCM determines the ambient light level is dark, the BCM supplies voltage to the exterior lamps.

Headlamps On With Wipers On Function 

When the headlamp switch is in the autolamps on position, the exterior lamps turn on when the front wipers are on. This feature does not activate the exterior lamps during a mist wipe, while the wipers are on to clear washer fluid during a wash condition or if the wipers are in automatic or intermittent modes.

The exterior lamps turn off when the ignition switches off or to accessory mode, the headlamp switch is placed in the off position, or the front wipers are turned off. The exception to this is when the exterior lights are on because of darkness determined by the autolamp system.

Stoplamps 

System Diagram 

Courtesy of FORD MOTOR COMPANY