2007 GMC Sierra 1500 Pickup Owner's Manual - Page 538

4. If a CHMSL bulb is replaced, put the new bulb into the socket and press it in until it is tight. If a cargo lamp is replaced, put a new cargo lamp bulb into the socket and press it in until it is tight before turning the socket counterclockwise. 5. Reinstall the back plate into the lamp assembly. 6. Reinstall the lamp assembly and tighten the screws. Pickup Box Identification and Fender Marker Lamps To replace a pickup box identification or fender marker lamp bulb, do the following: 1. Remove the screws and lamp assembly. 2. Unplug the lamp assembly harness. 3. Gently pry the individual lamp from the lamp assembly. 4. Unplug the lamp. 5. Plug in a new lamp and snap it into the assembly. 6. Reinstall the lamp assembly. 538