car?

Most electric door locks work with a very heavy solenoid to move the lock mechanism. These seldom fail. Have someone work the switch while you listen at the door for the solenoid "snap". If there is a snap, the mechanical linkage has failed in some way. Usually an easy fix by removing the door panel and repair the linkage. Be sure to lubricate all points of contact or it will happen again. If there is no "snap" then there is a problem with the electrical connection to that door. Most of the time, and due to age of your vehicle, the first place to look would be where the wires pass near the hinge as the constant bending break the wire. This happens quite often inside the wire insulation and is difficult to find. If it is electrical, and not at the hinge, these kinds of problems require a lot of time and patience as well as basic knowledge of electricity to find the open circuit. Good luck.

Rod
July 2009