Circuit Description
WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) uses the ambient light sensor signal in order to control the daytime running lamp system. The ambient light sensor is connected to the BCM through the signal circuit and the reference circuit of the ambient light sensor.