Greetings everyone.

The automatic door locks in my '82 245 Diesel wagon work fine in 3 out of 4 doors.

The left-rear door lock isn't working. Sometimes it moves part way, but most of the time it does nothing. As I say the other three doors work fine and I am not having any blown fuses or other electrical gremlins.

Everything feels normal when I pull the lock knob. It may be a little stiff but no different than the other 3 doors.

So I'll be pulling the door panel off to investigate soon.

To check the door lock motor, can I just disconnect the connector and apply 12V across the motor? Do I need to worry about polarity, or can I just try one way, and if that doesn't work switch? I presume that one polarity drives the motor closed, and the other drives it open.

If the lock motor checks out, the next step is to look at the voltage coming to it from the harness. I presume I can just attach a multimeter across the harness wires and watch the motor when I activate the lock system from the driver's door (using the key of course)?

If I replace the motor, is it pretty much plug and play, or is there a lot of adjustment required? Is that achieved by bending linkages, or are there threaded adjustments to me made? I'm sure some of that will be obvious when I get a look at the mechanism but I'd appreciate any thoughts from you that have done this job before.

Thanks in advance.

-Hendo