GMC 1999 Sierra 1500 Pickup Owner's Manual page 335

Front Parkinflurn Signal Lights
K2681
1. Remove the screws and take out the parking/turn signal light assembly.
K2682
2. Squeeze the tab on the side of the light socket while turning the socket
counterclockwise.
3. Pull out the socket.
4. Push in gently on the bulb, turn it counterclockwise and remove it from
the socket.
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