Sorry to leave you hanging. Was out of town all day.
This problem started with the redesigned '96 Caravan. I replaced a real lot of the lock motors on the sliding doors. There were two different things that could happen. Because there is so much stuff to move, a simple solenoid like was used for decades would not be strong enough unless it was really huge, so they use an electric motor now that runs a gear train to increase the pulling power. Most commonly the armature breaks free on the shaft and spins without turning it, or it will catch and release rapidly causing that buzzing sound.
The second problem is there is quite a shock on the gear train when the lock linkage comes to the end of its travel. That can result in part of the plastic housing cracking. That part holds a worm gear in place, and when it breaks, that gear can come out too far and get jammed. At that point no part of the linkage can be moved. If the door is locked, you can't unlock it. If it's unlocked, you can't lock it. There may not be any noise from that unit when it's locked up, but if that worm gear is able to move far enough, the gear driving it will chatter or buzz against it. With either defect the unit might work once in a while.
Those were separate lock motors in the sliding doors. In the front doors they were built into the latch assemblies. I'm pretty sure it was the same supplier that sold them to Chrysler that made both types, and they developed the same symptoms, so I would assume they break in the same way. I never autopsied a front latch assembly but I did replace a few.
Almost everyone uses this design now. What I would do is follow the lock knob's linkage down to the latch to see where it is clipped on, then disconnect it and see if you can move the knob and linkage. Chances are the linkages will move freely and the mechanism on the latch will be locked up. If you find the latch works okay but the linkage won't move, disconnect various linkages until you find what is binding.
Saturday, September 21st, 2013 AT 1:05 AM