Today, the battery on our 96 A6 Avant almost died after many weeks not running and the weather was cold. The weak battery some how caused the sunroof switch, gear and rails malfunction. The sunroof was opened all the way, turn the switch to close and it only moved in a little even the motor runs all the way, switch back and forth, tilt, open, close, the sunroof only moved a little, the gear and the rails seemed NOT to catch all the way. I was lucky, the weather was nice and NOT raining because the manual socket was stripped, I couldn’t close with the hex key, I need to remove the motor to see if I can fix the rails or motor gear.
Remove all the connected wiring and take out the console, clear from the sunroof.
The motor is secured with 3 torx T25 screws, need to remove them to drop the motor.
I was amazed to see the motor gears filled with dirt and plastic residue from turning the plastic rails, no wonder the gear teeth don’t catch the rails teeth. I used the small wire brush to clean the gear and the plastic rails teeth, where I could see.
I found the wire brush which was much better than this little screw driver , brush all the stuff and gunk off the gear teeth and some of the rails teeth. Plug back the power connector for the motor, screw the motor back in TIGHT (to make sure the gear gone up all the way to mate with the rails), plug the roof switch connector (console) to the motor, tried it out, and voila, it worked at every switch position. Plug all electrical connectors back and check again. The sunroof works great. I believe all Audi cars use the same motors or at least similar set – up, before taking it to the shops or dealers to replace motors, rails, or sunroof, at least tried this first.