i have a 99.5 a4 1.8t quattro. just recently it started acting up. i lock it and about 10 min later it unlocks itself. i uncovered the pump and it just freaks out like going on and off without me pressing anything. then it just randomly unlocks the whole car. which makes no sense that it stays unlocked cuz if u unlock it and dont open any door within like a min it just automaticly locks itself. but i need this fixed. i cant have an unlocked car! help!!!!

 

Check for vacuum leaks.

 

Chris,
It's most likely not a vacuum leak as I had the same problem and we have the same year car.

Mine was freaking out too and it killed the battery.

It is the centeral lock system you saw in your trunk and if you have VAG you'll find you can not access the central lock meaning it has to be replaced.

I bought a used one from a Audi salvage yard, www.Force5auto.com in Concord NH for $125. last summer and that was the end of that.
Jeff

 

Any water in it?

 

nope no water issues