I bought a FSM off eBay.
What problem are you haveing?
you could go to: RealOEM.com Online BMW Parts Catalog
type in your VIN or last seven digits, I think (been awhile)
and look at the microfishe if its mechanical. One thing that can be causing is the sliders. If the lubricant in the rails has dried out and become too gummy. It can make the window think it has hit a stop.
Adding extra lithium grease in the slider rails has helped many different issues with the windows.
Also, you might need to order some new sliders. The window glass has two aluminum channels glued/bolted on.
The regulator has two arms with swivel points that snap in to plastic sliders.
With the window mostly all the way down, you can see the arms through the openings.
The lubricant goes where the little rubber sliders are, in the rail.
Once your interior panel is removed, you could unplug the wire connector, test with your olm meter and see if ya get 12v when you hit the up/dn button to determine if its incoming electrical, like fuse or button. If you do, then replace the window motor.