I can't unlock or lock the driver's side door using either key I have--but it will unlock just fine with the key fob. Obviously, I want to fix this so I'm not stuck outside the vehicle if either the vehicle's battery or the one in the fob is dead. Any ideas on what to look for? I do know how to remove the door panel...

Oh, and I should say that the electric door lock mechanism was recently replaced--before that, it wouldn't always pull the lock down.

Thanks!