GMC 1999 Sierra 1500 Pickup Owner's Manual page 337

Fender Marker Lights
I
1. Remove the screws and take the lens assembly out of the fender.
2. Turn the bulb socket counterclockwise and remove it from the lens
3. Pull the bulb straight out of the socket.
4.
Put a new bulb into the socket and push it in until it is tight.
5. Put the socket back into the lens assembly and turn it clockwise to
6. Replace the lens and tighten the screws.
assembly.
tighten it.
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