GMC Sierra Owners Manual
Center High-Mounted Stoplamp (CHMSL) and Cargo Lamp
To replace one of these bulbs:
1. Remove the two screws and lift off the lamp assembly.
A. Cargo Lamp
2. On the reverse side of the lamp assembly, remove the bulb socket by turning it one quarter turn counterclockwise and pull it straight out.
3. Remove the bulb by pulling it straight out of the socket.
4. Install the bulb by pushing the bulb straight into the socket.
5. Install the bulb socket into the lamp asembly by turning it one quarter turn clockwise.
6. Reinstall the lamp assembly and tighten the screws.