Sounds to me like the door lock actuator is froze up. Open up the door, and between the door latch and the bottom of the door you'll see a rivet. Drill out the rivet and the actuator should move about freely allowing you to at least lock the door. The proper method would be to then remove the door panel and take out the actuator, but that part is up to you....
Stuck with door lock actuators that don't work and don't want to pay the $50+ for a new one? Tried the junkyard ones and found that they last six months and freeze up?
A new actuator for less than $4. Fix one side for $17, do both sides for only $23. I don't sell parts, I don’t make any money off of the upgrade, I just tell you how to do it cheaply and easily.