GM Service Manual Online
For 1990-2009 cars only

The Retained Accessory Power (RAP) feature utilizes the Body Control Module (BCM) to control the operation of the Power Windows and the Radio. It also controls the operation of the Rear Radio Control and Overhead Console (if equipped). The RAP Relay is powered by the RAP Fuse, and controlled by the BCM. When the ignition switch is turned to the OFF position, the BCM supplies a ground to the coil side of the RAP Relay. This allows power to flow through the Relay to the listed systems. The BCM will turn off the RAP system by removing the ground path from the RAP Relay if any of the doors are opened, or after 20 minutes when the BCM times out.