This morning my 1998 A8 had a totally dead battery (from sitting for four days with a weak battery, I assume). When I hooked up my big battery charger, the sunroof immediately opened, all by itself (switch in normal, closed position). And refused to close. I started the car; the sunroof still wouldn't close. I replaced the battery; the sunroof still won't close. Any ideas as to what is wrong or how to fix it?

If you take off the cover, I think it's a couple of screws. You'll see the allen wrench.

i've had the same type of problems, I've taken it apart and hit it with some contact cleaner. Seems to help.

It happened to me and I closed it with the tilt position and then I opened it again. Works fine since.

You should have the manual crank tool supplied with the car, its just a shaped hex wrench with long end, after removing interior light cover/ housing, just push up to disengage the motor and wind away.(look in manual shows picture)
I had this problem, the roof would work for days or even weeks, then suddenly stop in the up tilt positon so i took out the motor and cleaned all the contacts and the plug, seems to be ok now

bye for now