GMC 2003 Sierra 1500 Pickup Owner's Manual page 444

3. Press the release tab,
if equipped, and turn
the bulb socket
counterclockwise to
remove it from
the taillamp housing.
4. Pull the old bulb straight out from the socket.
5.
Press
a new bulb into the socket and turn the socket
6. Reinstall the rear lamp assembly.
7. Close the tailgate.
clockwise into the taillamp housing.
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