Side window left / stuck in up-position

[am99ey]

I experienced getting harder cranking over the last few weeks on the left side window. Suddenly it is stuck in the top position; no cranking possible anymore.
I have removed the door panel but can not detect the cause. All seems to be in place and nothing is bent. How should I proceed not to damage anything?
I have never had the door internals removed / repaired.
A drawing or picture might help me.
Thanks for a hint, Andy

 

[Series3Scott]

You might have a stripped door gear or some broken teeth on that gear. Unfortunately I'm afraid you may have to find a new winder mechanism. Replacing it (at least for me) was a nightmare but it can be done.

 

[Chuck Ingram]

The weather stripping can be loose and jammed the glass in the channel
I know this can happen and you need to loosen the front channel depending on what series it is

If it is a stepped gear sometimes it can be reversed depending on the damage.

 

[am99ey]

I have solved the problem.
(This weekend I had time to look closer at the problem)
The cause was a completely dried out crank axle.
I applied carefully universal grease out of a spray can (for bicycle chain, hinges etc..) also on all relevant mechanism. This helped immediately and windows sliding smoothly up and down now.
At the same time I checked and retighten the screws of the window guides.
Thank you for the hints.
Andy