I have a 1998 A6 Quattro that is driving me nuts. Several weeks ago we had a monsoon of a rain storm and we got water into the car in the area of the left kick panel. I found that it got in through a small hole near the top of the firewall on the drivers side. Water had collected under the carpet on the driver side and by the time I could get it all vacuumed out, we started having electrical problems. At first, the windows and sunroof would work intermittently and finally they just quit working at all. Now, the power windows, the sunroof, the power door locks and the remote control for locking/unlocking the doors doesn't work. Which also includes the alarm system.
I have checked all fuses in the dash, side panel and they are okay.
Does anyone have any idea where I can look to resolve this problem?
Thanks

 

Pull up the carpet, I'm quite sure you have an electrical module somewhere, look under the seat. When this module gets wet it will short out, probably needs replacing.

 

If its the same as my 02 the module is under the carpet in front of the seat about where your feet would be if you sat in the driver seat with your feet flat on the floor. It is inside of a plastic box which is probably full of water. You may also want to check the transmission module to see that it has no water in it it is located in the same position but on the passenger side.

 

I drove a 2003 A4 1.8t that had the exact same problem. The guy was selling it cheap because he could not fix it.

 

Check under the back seat passenger side next to the battery for a large grey foam block. The central locking comtrol module is inside the foam. Water runs to the back of the car and soaks the foam and the electrical connectors on the module. Open the module, spray with electrical cleaner, dry with a hair drier. Reassembly is reverse of disassembly.

 

HI THERE I HAD SAME PROBLEM (IT IS COMMON PROBLEM FOR AUDI).U have to clean contacts(they probably acidise) on your mane computer which is under carpet of driver's side,and try to keep it dry.

 

Be sure to look at the central locking and get a new/used one. Make sure that all the crimps that are in the wiring harness are good. If water sat in there for a while than the crimp in the wiring harness could have crowded bad.