GMC 2000 Sonoma Owner's Manual page 284

Taillamps
1. Open the tailgate.
6-42
2. Remove the screws from
the lamp assembly near
the tailgate latch.
3. Pull the assembly away from the pickup side panel.
4. Turn the socket counterclockwise to remove it.
Push the tab in while you turn the socket.
5. Pull the bulb out.
6. Push the new bulb into the socket.
7. Put the socket into the assembly and turn the socket
clockwise until it locks in place.
8. Replace the assembly. Install and tighten the screws.
9. Close the tailgate.