Daytime Running Lamp: Description and Operation

DAYTIME RUNNING LAMPS (DRL)

The ambient light sensor is a light sensitive transistor that varies its signal to the body control module (BCM) in response to changes to the outside ambient light level any function or condition that turns on the headlamps will cancel the DRL lamps operation. With the headlamp switch in the OFF position, the turn signal lamps will either be turned ON or OFF after a 30 second delay, depending on whether daylight or low light conditions are sensed by the ambient light sensor. The DRL operates when the ignition switch is in the RUN position and the parking brake is not applied, or the transmission is not in PARK. When these conditions have been met and the ambient light sensor indicates daylight conditions, then the BCM will illuminate the front turn signal lamps ON steady.