Backup Lamps
WARNING: This page is about a different car, the 2002 Pontiac Montana, 2002 Oldsmobile Silhouette, and 2002 Chevrolet Venture. However, it is still accessible from the selected car via links, so may be relevant.
The B/U LAMP fuse in the junction block - underhood, supplies battery positive voltage to the transmission range switch. When the driver places the gear selector lever in the REVERSE position, the switch closes and the current flow is through the backup lamp switch to both backup lamps. The backup lamps are grounded at G401.