2004 GMC Sierra 1500 Pickup Owner's Manual - Page 469

Center High-Mounted Stoplamp (CHMSL) and Cargo Lamp 1. Remove the screws and lift off the lamp assembly. A. Cargo Lamps B. Center High-Mounted Stoplamps 2. Remove the CHMSL bulb holder back plate from the housing by pressing the release tabs. 3. Remove the CHMSL bulb by pulling the bulb straight out from the holder back plate. Remove a cargo bulb by turning the socket counterclockwise and pulling the bulb straight out. 5-69