For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningBuying New Tires
GM has developed and matched specific tires for the vehicle. The original equipment
tires installed were designed to meet General Motors Tire Performance Criteria Specification
(TPC Spec) system rating. When replacement tires are needed, GM strongly recommends
buying tires with the same TPC Sp ...
Taillamps, Turn Signal, Sidemarker, Stoplamps, and Back-Up Lamps
Trunk Deck Inboard Taillamps
1. Open the trunk.
2. Remove the trunk deck trim cover (1).
3. Remove the bulb socket (2) by turning counterclockwise and pulling straight out.
4. Remove the bulb from the socket.
5. Install the new bulb in the bulb socket.
6. Install the bulb socket by turni ...
Dome Lamps
The dome lamp controls are in the headliner.
(Dome Lamp Override): Press
to turn the lamps off, even when a door is open.
(Door): Press to turn the
lamps on automatically when a door is opened.
(On): Press to turn on the
dome lamps. ...