Another WILD guess here...it's the same mechanism that controls the sunroof. Alot of us B5 owners have had problems with the sunroof magically opening whenever it feels like. It's generally corrosion up inside that switch. You might want to pull it out, there's a write up at passatworld to clean the solder points and how to remove it
http://www.passatworld.com/forums/sh...d.php?t=238398
...it could just be that, since when you turn the switch OFF they stay off....just a guess....

 

Cool. I hope it's just that. My sunroof has been ok except for the last time I got in it, so something's going on up there. I'll definitely check it out. It's in the shop now, so as soon as it's out I can start poking around. I'll keep everybody posted if I find out. Thanks for all the suggestions! Electrical problems are definitely a pain, but I still feel lucky after reading some people's problems.

 

I have exactly the same problem. It all started when the washer fluid tube for the rear window separated (due to it being frozen) and spilled a couple of liters in the right compartment in the boot.
At the bottom of this compartment is a unit that controls the interior lights, remote door lock, etc, as well as containing the vacuum pump for the door locks. Apparently something has been short-circuited due to the washer fluid.
I got three of these units at the scrapyard, but none will work. Had the car at the local repair shop (not Audi), and they said there was an error flag which could not be reset, they believed it was some sort of "black box" functionality. Anyone has any idea how to reset this?