Relay Control of Retained Accessory Power (RAP)
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2004 GMC Yukon XL, 2004 GMC Yukon, 2004 Chevrolet Tahoe, 2004 Chevrolet Suburban, and 2004 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) keeps the retained accessory power (RAP) relay energized during all power modes, except Off-Awake.
The device powered through the RAP relay is the sunroof.