Cadillac 2009 CTS - Manual (Page 366)

3. Remove the electrical connector from the bulb by
lifting the two plastic clips.
4. Remove the bulb socket from the lamp housing
by turning the bulb socket one-quarter turn
counterclockwise.
5. Pull the old bulb from the lamp housing keeping the
bulb straight as you pull it out.
6. Install a new bulb.
7. Reinstall the electrical connector by pushing in the
two plastic clips.
8. Push the bulb socket into the lamp housing and
turn the socket one-quarter turn clockwise.
License Plate Lamp
To replace one of these bulbs, do the following:
1. Push tab to remove the license plate lamp.
2. Turn the license plate lamp assembly down to
remove it.
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