Ok, found a way to open up the motor without removing it. The plastic cap covering the circular contact area just popped off, and I was able to clean most of the grease out of there using a cloth and brake cleaner. Put the cap back on and tested the wiper: nothing.
It looks like i'm getting power to the motor, but nothing is happening. I've got to test the motor for resistance now to see if its shot. Any tricks to test it without removing it? If not, I'm gonna have to get it out, and I just don't know how to separate it from the linkage and get it out of the plenum. I've gone to BP's page with pics on how to do it, but he has a 318 and the setup looks different to my '84 325e.
Thanks in advance,