I have a 98 A4 Quattro and whenever it rains, my car will lock and unlock by itself(sometimes i have to struggle to get it to unlock with the key), windows go up and down, and it will alarm with me in it! I'm not sure if theres a leak in the sunroof drains or not? Once it dries though its fine...Please help!

 

I have an A6 Avant. Found that there is a ECU under the front left footwell. I believe that this controls the central locking and windows etc. I found that mine was swimming in water from a leak. Remove trim and pull carpet up to check. If this is the case you have a leak somewhere. I am still working on mine. I have checked and modified the A/C drain and also checked and cleaned the drain under the batery. These are only two problems that could cause this issue. If your car has a sun roof the drain for this could also be be blocked. This shold drain from under the door hinge.

I hope this helps

JC66

 

On the A4, the battery sits in a well, just under the windscreen.

Underneath the battery are two holes which allow water that runs into that area (from the windscreen) to drain away. Leaves and other debris block these and cause the well to fill with water. If it gets across the battery terminals on low height batteries it will cause problems.

The other issue you will have is that eventually it will fill up and drain into the cabin via the cabin air filter. After a heavy downpoor you will literally hear water running/swishing about in one side of the cabin floor.

This is an easy thing to check but it will involved removing the battery and clearing those holes.

For future maintenance, always remove leaves and other things that you can see from under the bonnet edges. Also, every time you replace a battery, have the technician (or do it yourself) clear those holes out.

Good luck