GMC 2008 Envoy - Manual (Page 346)

4. Unclip the wiring harness (A) and remove the
three socket retaining screws (B).
5. Remove the socket plate.
6. Holding the socket, pull the bulb to release it from
the socket.
7. Push the new bulb into the socket until it clicks.
8. Reinstall the socket plate and tighten the
three screws.
9. Reconnect the wiring harness.
10. Reinstall the taillamp assembly by lining up the
locator pins with the retainers in the body of the
vehicle.
11. Reinstall the two screws and tighten.
12. Close the liftgate.
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