Sunroof strangeness

[newsh]

Preselect sunroof with rotary control.
Every now and then I go to close the sunroof and it closes then goes to fully open and stops. Sometimes you can open and close it again and sometimes it will just go back to fully open.
Is there something I can adjust? I'm worried that one day it won't close when I need it to!

[UrS4boy]

Preselect sunroof with rotary control. Every now and then I go to close the sunroof and it closes then goes to fully open and stops. Sometimes you can open and close it again and sometimes it will just go back to fully open. Is there something I can adjust? I'm worried that one day it won't close when I need it to!

While it might be an issue with the contacts on the rotary control being dirty, the symptoms you describe are often a result of a dieing battery (low voltage). While I can not find any documentation on this, I believe it *might* be a safety feature related to the car ending up in the water in an accident or trapped in a flood. As a last effort, with the last bit of voltage available, the sunroof opens to release the otherwise trapped passengers/driver. Replacing the battery has typically solved the problem.

[newsh]

Battery is new and fully charged AFAIK. I will try and see if there is a difference between closing with the engine running and not running. I have to say that the Sunroof Underwater Safety People EsCape Technology (SUSPECT) feature seems unlikely

[UrS4boy]

Battery is new and fully charged AFAIK. I will try and see if there is a difference between closing with the engine running and not running. I have to say that the Sunroof Underwater Safety People EsCape Technology (SUSPECT) feature seems unlikely

SUSPECT = good one!

All I know is strange sunroof opening behaviour is very common on cars with dieing batteries, whether that was a design feature or something that just happens.

Otherwise, check and clean your contacts in the switch. The panels are typically just clipped up there. Ask how to remove the B3/B4 panel because the plastic is very brittle and brute-forcing it will break the plastic tabs.

[newsh]

Yeah, 2 of the tabs are already broken, you have to pull down the side nearest the screen first then unhook the side nearest you..

Anyway, switch disassembled and contacts and track wiped with a little GT85, some dirt came off the potentiometer tracks. Seems to work ok now, I tried it several times, opening both ways and closing again.

[TimE-J]

just a quick question but how did you remove the switch from the panel?

[newsh]

As the switch is actually a potentiometer then the different positions will give different volteges. If the battery is low then the voltages will not be correct so very possible that the roof would behave strangely.

[newsh]

just a quick question but how did you remove the switch from the panel?

I didn't, I prised the back off the switch with it still on the panel

[TimE-J]

ah right ok, do you know it is possible to remove the switch, I've just had a thought about mind but I'm nowhere near my s2.

[andyg plym]

john,i had this on my old 3b and it was the relief relay

[mcandmar]

The pre select sunroof is a pain in the **** in my experience. Its certainly a dodgy potentiometer, a clean with elecy cleaner will usually bring them back for a while but they will play up again. Never bothered looking into replacements, i doubt Audi will sell the pot on its own but im sure you could source one from an electronics supplier.

[djh]

or speak to acidburn he has quite a few still kicking around.

When I had my other car it was a pita to get the sunroof to open a certain amount.

[newsh]

Its a strange looking pot inside, I should have taken a pic of it, has about 4 or 5 tracks and contacts If it plays up again I will use some special fader reconditioner I have at work. http://store.caig.com/s.nl/it.A/id.2631/.f

[Error404]

the pot is available as a spare from the dealer IIRC its about £50
I wonder if a £2 part from Maplin will drop into the OE pot housing?

I still need to buy some of that stuff John sounds like gut scheisse

[newsh]

Not sure how the pot is removed but I'm guessing you pull the knob off (like a heater control knob) and there's a nut or a couple of screws underneath. I gave it a tug yesterday but it didn't move easily..

Yes, the Caig products are great, fix electrical problems on the car and will make your hifi sound better too!