It could also be the door lock solenoid. Usually they go out at all at once rather than sporadically working and then not. If you take the inner door panel off and all the linkages seem ok, then it's the solenoid. In the wisdom of the Dodge engineers, they integrated the solenoid into the lock, so you have to replace the thing as a whole unit. I took mine apart when it failed because I have successfully repaired door locks on other vehicles, but not this time.... I ended up getting a used one off ebay.