My '93 Concorde/Intrepid had a driver door lock that failed to work with the door button or transmitter. The part was hard to find ($100), so I had to repair it. After removing the door panel and the three screws that mount the lock to the door, I found that the lock motor is contained in a sonic-welded black plastic module (not designed for repair). With a little work with an Xacto knife and a bit of prying, the module popped apart and the motor could be removed (remove the press-on brass gear from the motor shaft). "Unbend" the metal tabs holding the motor together and pull it apart. Use a spray of electronic cleaner (or brake cleaner), spray the commutator to clean it, and ALSO spray the contact points along the inside of the metal case (didn't see them at first, but they're where the power input pins connect to the brush wires). Use a mototool to enlarge the motor shaft hole a few thousands of an inch to allow the gear to be passed through, or just re-press the gear onto the shaft after putting the shaft through the hole. Applying power to the motor shows it now works perfectly. Use a two-part plastic epoxy to reassemble the housing, and re-assemble the mechanism.
I saved about $100, but spent about three hours of work. Worth it? Yes - I fixed it myself, know a lot more about the lock mechanism, and got out of some "Honey-Do's" for a bit.