The lock on my driver's side door does not lock or unlock. The passenger's side door lock works. My keychain lock will unlock the car, but not lock it. Can someone point me to a solution?

 

Welcome to the forum. It sounds like you have at least two separate component failures. What's the accident and/or repair history?

 

The only accident involved the radiator being replaced. I also took the car in for the 2005 Cobalt steering column recall. They replaced a electric component for the steering.

 

Okay, I never know what to expect with a Cobalt, what with kiddies playing with the wiring.

The driver door lock switch problem is probably the switch itself. Take the pull handle/switch assembly out (see How To Remove Car Door Panels On A 2007 Chevy Cobalt), disconnect the electrical connector from the door lock switch, and then momentarily short the WHT and BLK wire electrodes in the connector with a paper clip or something to send a signal to the BCM. If the wiring is good, the door lock actuators will go ka-chunk, proving a bad switch.

The key fob problem is probably the key fob itself. You can try taking it apart and repairing the button contacts. Or, purchase new ones from the dealership or eBay (match the GM/L number on the back of key fob) and have the dealership program the vehicle. Automotive locksmiths can do the programming as well.