A6 central locking problem

[Leo]

Hi all, new boy here. I'm having probs with the central locking system (control unit I think) on my '99 A6 1.9 tdi. Since being sat idle for 2 weeks over Christmas, the first drive out was a scary one for the kids. The windows - all of them - opened while we were driving along, and at the same time the doors locked/unlocked themselves and the interior lights flashed. Then, when we stopped, the doors locked and we couldn't unlock them (clever system on the Audi's), but luckily the key-fob unlocked them ok. I first thought it may have been due to low battery voltage, but that's fine, charging well and holding it too. Next guess is the central-locking control unit, but where is it on the car and approx how much will a replacement cost? It may just be damp after the two-week holiday (I'm hoping), so a hair-dryer or a day on the kitchen radiator might sort it out. Hate having to pay the dealer for summat I can do myself. Any help will be gratefully received.
Leo

[Leo]

Hi everyone. Just thought I'd tie this one up.....it would appear that my first instict of it being damp that got into the central locking control unit may have been right.;) The problem disappeared (thankfully before it got as far as the Audi dealer!) when the car started getting used again, and the recent dry/windy weather has probably done its share to help too. Here's hoping it's gone for good!

[demonbarber]

I have a very similar problem on my 1999 Audi A6, if you open all doors via the remote the windows open and interior lights go haywire. I assumed that the damp had got into the control unit as it is under the passenger footwell in a plastic box. If I open just the drivers door via the remote everything is fine, then I can press the button on the drivers door to open the other doors.
My problem is still present because we are still having lots of wet weather and the car hasn't really dried out inside.

[Leo]

A bit more info for you...the A6 was misting up badly so I checked the carpets and the passengers footwell was sopping. Looked under the bonnet and the area that the battery sits in in front of the windscreen was 4" deep in water, so every time the car went around a corner water lapped over the pollen filter and down into the footwell - and possibly over and into the central locking control unit. The cause of the flood was a blocked drain (underneath the battery tray) which was clogged with leaves. Once unblocked all seems to have been ok since. Hope this helps.
Leo.

[demonbarber]

Thanks for your reply Leo. I had that problem about a year ago, I dried the carpet out as much as possible. I was worried that any remaining damp had caused the circuit board to corrode, but upon inspection found it to be totally dry. Have found several more posts with people saying the microswitch on the drivers door lock or where the wires go through the rubber grommit into the door pillar. I will hopefully check at the weekend and keep you posted.

[paul b]

A bit more info for you...the A6 was misting up badly so I checked the carpets and the passengers footwell was sopping. Looked under the bonnet and the area that the battery sits in in front of the windscreen was 4" deep in water, so every time the car went around a corner water lapped over the pollen filter and down into the footwell - and possibly over and into the central locking control unit. The cause of the flood was a blocked drain (underneath the battery tray) which was clogged with leaves. Once unblocked all seems to have been ok since. Hope this helps.
Leo.
Yup, the common, dreaded Plenum chamber fault.

[Peter D]

Enter Plenum Chamber in the search box it's all there. Regards Peter