Hey: My 92 325i is having problems with windows rolling down.
Problem: When I start the car the window button lights are on and they willl roll up and down for about a 1 minute.....after that they are dead, the lights go off, and the windows will not respond. Wierd...sorta like they are on a timer or something like that....any clues? Thanks all....
Scott

Maybe the comfort relay . . . try this . .

http://members.roadfly.com/petah/e36comfortrelay.htm

Most definately sounds like the comfort relay. I had the same problem, I took the relay apart and resoldered the bad connection and it's worked like a champ ever since.