GMC 2007 Sierra - Manual (Page 536)

2. Install a new bulb
into the socket and
turn it clockwise
until it locks
into place.
3. Reinstall the lens and tighten the screws.
To replace a center roof marker lamp bulb, do the
following:
1. Remove the six screws from the center roof
marker lamp assembly.
2. Turn the old bulb counterclockwise to remove
it from the socket.
3. Reinstall the lens and tighten the screws.
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