Circuit/System Description

The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 1.4-4.5 V depending on outside lighting conditions. The body control module (BCM) monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control when the headlamp switch is in the AUTO position. In daylight conditions the BCM will command the DRL and rear park lamps ON.

The BCM receives a signal from the ambient light/sunload sensor indicating a low or high ambient outside light level. Under daylight conditions the BCM will enable the daytime running lamps and rear park lamps. The daytime running lamps and rear park lamps share the same BCM control circuit. With the headlamp switch in the AUTO position, the DRL and rear park lamps will be illuminated at all times with the ignition on and engine running.