I had the same problem. Try this: take off your door panel and peel back the plastic film from the door handle. When you pull on the handle, you'll see one of two metal wires move. Follow the metal wires all the way back to the edge of the door, making sure to pull back all the plastic film around the metal wires. Pick up a can of trusty WD-40 and spray all over the wires where you see them dissappear in the doors edge and then spray behind the door handle itself. Spray a lot and then move the wires back and forth with your fingers and with the door handle and door lock. Do it a few times and it should help a lot. Sorry this was so long.

I had the same problem, but in my blazer.

Check the switch. If it works sometimes, it may be resistance withing the switch.

ohm out your switch with it open and then again with it closed.

u should get a beep with it closed and read infinity with it open.

then check your wires for power and grounds, try to wiggle the wiring a litttle when u check your readings that way u will be sure there isn't a fray in the wire somewhere.

I replaced the switch on my car and it worked like a champ.

Later, good luck

Yeah, I have the same problem. When I lock the doors using the driver side lock, the passenger side lock handle only moves halfway and unlocks (since it wasn't completely locked). The weird thing is that it started working perfectly fine 100% of the time for about two days, then quit again. Normally it never works, so I have to reach over and use the passenger side lock to lock my doors.