Having the sunroof pop open randomly was really one of my Audi's more charming quirks. Much more personality than say... an ABS module that is on it's way out and beeping while you're on the phone...

"What's that annoying noise?"
"oh, that's just my fancy German car being a POS, let's talk about you."

...But to keep me from being surprised on a rainy day I opted to try and fix the problem. Also my interior lights occasionally needed a tap on the switch to work when the door was open.

This has probably been written up a several times but I never saw it with the close up pictures so here's another one.
(This was done for my 1998 A4 Avant Quattro 2.8L Tiptronic Sport Pkg + Cold Weather)
If you're a safety ranger you could disconnect the battery. But if you're a saftey ranger you don't really have to be told that.

Remove the control assembly from the roof:


Remove 2 average sized phillip head screws:


Carefully pull the module down and disconnect the 2 cables:






Next, more carefully than I did pry the back off the round switch part.




You can see that I cracked the housing a bit, you can do better, I believe in you.


Now with the switch open you can see how it works. (you may not get through the next paragraph if you're ADHD)

There's a couple of sets of wipers that run along a resistive surface. The voltage will vary from 5 volts to 0 volts depending what end of the surface the wipers are contacting. For instance 2.5 volts would be the switch setting for the roof to be closed. 4 volts would be the point where the roof should be open, and at 1 volt the rear of the roof should be popped up. (I made those numbers up) The demons live in those black tracks on the resistive surface. While the wipers are parked at the 'roof closed' position those black tracks are messing up the connection between the wipers and the surface. This causes the wrong voltage to get fed to the motor controller and it sometimes sees 1 volt instead of 2.5 volts and it opens the roof for you. To fix this just clean up the resistive surface, and the wiper contacts.


A pencil eraser works fine to clean the surface without being too hard on it. Also clean up the wipers if needed, be careful with the wipers they look fragile. Final clean up with holy water or contact cleaner and you're set.


While you're in here, clean the interior lights contact too. You'll have to remove two more small phillips screws and pull the connector off. Kind of hard to get at the contacts but try and brighten them up a bit to keep things working for a while longer.


Snap everything back together and you 'should' have a reliable switch again! At least it worked for me... so far.

(note: the demons are not actually removed from the car, they are simply displaced. And now they're mad and they're going to go make oil sludge or something like that.)

 

Nice photos. Holy water helps as does playing Tubular Bells on the CD.

 

cleaned my contacts, worked, problem came back, cleaned, worked, broke, bought new switch, broke, cleaned, worked, broke, removed fuse and no longer use sunroof. waiting to remove that piece of **** for weight reduction.

 

Chaos,
I can vac bag CF up to 18"x18". I haven't used the stuff in a long time but if the distance were less I'm mock you a CF b5 sunroof delete. It'd be hand laid and not vacced, but the part just needs to be watertight and look good, it's not for structure right?

-Ryan

 

About that sunroof, when you have it completely open and retracted, does the little sunroof cover get pulled back into your headliner so you have to squeeze your hand in that little slot to pull it back to the front of the car? I hope you guys know what I mean.

 

hmm that's not an encouraging story you tell chaos, I'll expect the worst and hope for the best.

 

lol i take that attitude with anything to do with this car


and rsrbljan- that would be really cool, only im putting all my money towards a t3t4 setup right now, but as soon as thats done i just might hit you up on that, thanx

 

Thank you for your clear and humorous DYI! I was able to clean my switch and have a normally functioning sunroof due to your post. Thanks for believing in me as I was able to avoid cracking the switch housing, although I can see how that could easily happen. It helped to be on high alert.

There should be more humor with these things! We need all of that we can get in the process of keeping our old B5s going. These projects that can sometimes feel intimidating.

BTW, the demons have been banished to the trunk for now, where they can do minimal damage, unless they figure out how to remove the fuel pump cover.