WARNING: This page is about a different car, the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Install the bulb into the socket.
Index the socket tabs to the backup lamp housing slots.
Position the socket to the backup lamp housing.
Rotate the socket clockwise until the retaining tab (1) is fully seated.