Drivers window won't go down, replaced switch, no change

[andrewwynn]

This is the relay or switch. Logically a relay since the driver window can be remotely controlled.

Have you tried to use the auto down function of holding the door key in the unlock position until all the windows roll down ?

As you can see from the diagrams if you have power for up you have power for down. I marked the suspect trace with yellow.

Since BMW would never repair the inside of a module I suspect they simplified the diagram.

Internally there is almost certainly a switch that is probably a single pole double throw switch that hits the double throw relay so you would have the down side of that wiring to look at as well.

If the switch doesn't work but you can roll down the window with the key it's the switch that's broken.

If neither works it's the relay.

In either case swapping the door module from a parts car should fix the problem.

[wpoll]

Originally Posted by andrewwynn

... Since BMW would never repair the inside of a module I suspect they simplified the diagram.

...

Boy, this thread went places overnight...!

Yes, BMW certainly simplify the block diagrams. When I said there was no relay, I meant an external socketed relay, as used in many other locations. User replaceable...

Sometimes the symbols on the block diagrams represent a relay and sometime they represent a solid-state switch. Interesting to know that in this case, it IS actually a relay. Interesting choice of design too, given the other highly integrated circuits on this board.

I think boards these get wet when you sit in the rain in the McD's drive-through and the water always sits in the same place, hence the similar failure mode on multiple units. Seems like an easy fix though, esp. since Boston01X5 has a spare unit he can send to you Andrew.

And yeah, de-soldering can be a pig - I have a vacuum de-solder too (Pace) ! Love it!!