Foot Well Courtesy Lamp
WARNING: This page is about a different car, the 2002 Oldsmobile Intrigue. However, it is still accessible from the selected car via links, so may be relevant.
The foot well courtesy lamps are turned ON by the dimmer switch or during illuminated entry.
During illuminated entry or when the dimmer switch is ON, the body control module (BCM) wakes up and then energizes the courtesy lamps supply voltage circuit, suppling voltage to all interior lamps. The BCM pulls the interior lamp control circuit low, providing ground to the foot well courtesy lamps and all courtesy lamps.