E30 Zone

passenger window on my cab is very slow...the first six inches is ok then it really struggles then picks up speed again the last couple of inches and sounds like its struggling..its also the same on the way up...could this be the switch

Ha ha ha, i have exactly the same problem on my cab, not the switch as i have swapped them over.

The rails i think run some thing like a screw driver up it.

I have this problem on the driver's door in my E30 too so would be interested to know if there's an easy fix for it as it's quite annoying.

I have this on my drivers door, and the passenger side doesn't work at all! I may strip the door down and give the regulator a good clean/grease and see if this helps. I'll check the voltage at the motor too and see if it's receiving full power!

If I find anything, I'll post it up.

Phil

It could well be a tired motor which will obviously need replacing if this is the case.
However it may also be that the mechanism is out of alignement and the only way to see for certain is to remove the door cars and watch the mechanism as you operate the window.
Whilst your at it clean out and lubricate the sliders etc...

It will not be the switch as the switch itself has no bearing on the speed the motor runs at.

as spadge says service the windows ..get them straight and grease the runners with a silicone spray

there should be a how to in the wiki