Driver Window not Dropping

[Strawfordt]

Okay, I have been in the window regulator manufaturing business for about 13 years. I've been mostly dealing with North American domestic regulators.

Is this a sudden problem or one that has existed for ever?

If this has suddenly occurred here's what I can recommend you to do.

You will need to remove the door trim panel to allow you to see inside the door
The window regulator should be a 2 rail, cable and drum type. The motor will have a plastic drum housing that contains the cable drum that winds and unwinds the cable. The cable will feed into the drum housing in two places that will be approx. 180 degrees apart from each other. If you can see where the cable is fed into the drum housing you should also see that there are 2 springs that take up the cable slack. When you change direction you will see one side of the cable collapsing the spring and the other side of the cable having the spring move to extension. This is done to take up the natural slack and / or stretching of the cable. I suspect that you will see the side with the spring extension being > 25mm from the housing. BTW when you reverse your window the springs will switch from extension to compression and vice versa.

If you are seeing excessive spring extension then in all likelyhood the cable has either come off of one of the pullies, a plastic end piece has failed on one of the conduit ends or the cable assembly was built to long to begin with. For what ever reason what you are describing is an excess of free cable causing the cable drum to wind cable without causing the glass to move.

The glass drop function in the window regulator and the express up function are both controlled with a logic controller and hall effect sensors in the motor that send a signal to the controller allowing the controller to count the rotations of the motor armature. If you can detect time and speed of the motor then you should know position.

If you still have problems let me know. In the meantime i'll try to get you a picture of a Box W/R to highlite the areas I'd be looking at.