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.
When the headlamp switch is turned to the PARK or HEAD position, the body control module (BCM) applies battery positive voltage to the I/P courtesy lamps. When a door is opened, the door latch assembly applies a ground to the BCM. The BCM supplies battery positive voltage to the courtesy lamp supply voltage circuit and applies a ground to the courtesy lamps control circuit.