This thread title sounds dirty, but it isn't. The rear wiper on my '99 A4 Avant has been acting jerky. When I turn it on, it will rotate about 2/3 of the way through its initial arc, then stop for about half a second, then complete the initial arc and begin it's return arc, only to stop for another half second, then continue back to the starting position. Normally, when operating properly, it would stop after one cycle before pausing to start one more complete cycle, but after one jerky cycle as described above, it will continue another jerky cycle back and forth. It seems to be trying to rectify itself and get back to the starting position in the middle of a jerk, so it takes 5 or 6 cycles before it comes to a complete stop. Any thoughts on if this might be the wiper motor, or the relay, or....?

 

Update: I've found that if I turn the rear wiper on and leave it on, the jerkiness will work itself out, and after about 10 or so jerky cycles it will start operating smoothly and with a single motion for each swipe. So it's like it has a cold starting problem.

Anyway, still looking for some input on what might be causing this. Also, anyone know where I can find instructions on how to get to the rear wiper motor and investigate further?