I have had consistent trouble with the drivers-side power seat in my 1996 960. The right side has jammed about 8 times. This has required that I laboriously disconnect the right side cable and spin it with a power drill to run the seat forward and back. Once I do this, I have always reassembled it and it worked fine for awhile. After the last incident it still wouldn't work. I went through the procedures in the FAQ to fix any potential problem with a short cable between the motor and gears with no luck.

Eventually, I found a used seat mechanism at an auto dismantler and that prompted me to disassemble the current jamming gear housing. What I discovered was that the large gear was binding because the gear bushing (that is press fitted into the metal plate) had loosened. This caused the gear to bind just enough that it took great force to spin it. I could hammer the small gear or the shaft and realign it but it was almost impossible to keep it perfectly straight or to not have it shift out of place again. I ended up replacing that whole side gear mechanism with the used one from the auto dismantler. That resolved the problem.

I hope this helps others diagnose their seat jamming if they have the same problem.