Expert: Don Berlan - 12/17/2007

Question
All of the windows have lost power. I have checked all fuses under the hood and all are good. Pulled the window lockout switch and checked for power and continuity. There was no power, however the switch was good. Is there a relay switch or another inline fuse somewhere? I am completely lost. I bought a Chilton's manual and found NO reference to the window power or switches at all!! I need help..........

Answer
Many times you would think the wiring is good but actually it is corroded inside the wiring cover itself.You have for sure a wire that is internally corroded.You need to check all the connections including those under the dash,along with all the ground connections(which are brown wires)

I have reread your answer and my reply.The Chiltons that you bought did it give you any wiring diagrams?That would help you out.I can't recall all the wiring diagrams in as many cars as I work on but I did look around and found some help in a Haynes manual.(They have wiring diagrams in the back of the manuals)There is a safety switch which shuts power to all the windows.It gets power from a relay.You need to trace down the safety switch(If it was a 5 series it is in the Knee bolster,in a 3 series I too would have to look for it.)
Your comment about checking grounds tells me your not familiar with BMW's.The relay that controls the safety switch relies on a good ground to work.I know it doesn't sound very informative,you really need to buy a Haynes manual it would help(BMW 3&5 Series 18020).