GMC 2007 Sierra - Manual (Page 538)

4. If a CHMSL bulb is replaced, put the new bulb
into the socket and press it in until it is tight.
If a cargo lamp is replaced, put a new
cargo lamp bulb into the socket and press
it in until it is tight before turning the socket
counterclockwise.
5. Reinstall the back plate into the lamp
assembly.
6. Reinstall the lamp assembly and tighten
the screws.
Pickup Box Identification and
Fender Marker Lamps
To replace a pickup box identification or fender
marker lamp bulb, do the following:
1. Remove the screws and lamp assembly.
2. Unplug the lamp assembly harness.
3. Gently pry the individual lamp from the lamp
assembly.
4. Unplug the lamp.
5. Plug in a new lamp and snap it into the
assembly.
6. Reinstall the lamp assembly.
538