To replace one of these bulbs:

1. Remove the two screws holding each of the license plate lamps.
2. Turn and pull the license plate lamp toward you through the opening.
3. Turn the bulb socket counterclockwise and pull the bulb straight out of the socket.
4. Install the new bulb.
5. Push the bulb straight into the socket and turn clockwise to reinstall.
6. Push and turn the license plate lamp away from you through the opening.
7. Reinstall the two screws holding the license plate lamp.
Back-Up Lamps (Coupe)
Replacement BulbsChevrolet Cobalt Owners Manual. Towing a Trailer (Automatic Transmission)
WARNING:
The driver can lose control when pulling a trailer if
the correct equipment is not used or the vehicle is
not driven properly. For example, if the trailer is
too heavy, the brakes may not work well—or
even at all. The driver and passengers could be
seriously injured. The vehicle may ...