2010 GMC Sierra 1500 Crew Cab Owner's Manual - Page 528

Taillamps (Chassis Cab Models) 4. Install a new bulb into the socket, turn it clockwise, and press it in until it is tight. 5. Reinstall the lens and the four screws. License Plate Lamp To replace one of these bulbs: 1. Reach under the rear bumper for the bulb socket. A. Backup Lamp B. Stoplamp/Taillamp/Turn Signal Lamp To replace one of these bulbs: 1. Remove the four screws. 2. Lift the lens off the lamp assembly. 3. Turn the old bulb counterclockwise and pull the it straight out from the socket. 6-68 2. Turn the bulb socket counterclockwise and pull the bulb socket out of the connector. 3. Pull the old bulb from the bulb socket, keeping the bulb straight as you pull it out. 4. Install the new bulb. 5. Reverse Steps 1 through 3 to reinstall the bulb socket.