Rear Compartment Lamp
WARNING: This page is about a different car, the 2009 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
The BCM supplies battery positive voltage from the INT LAMPS fuse through the inadvertent power courtesy lamps circuit to the rear compartment lamp. When the rear compartment is opened, the rear compartment lamp switch closes to ground and the lamp illuminates.