I was driving along & went to wind window up & it stopped halfway with clicking noises. I was able to close window by pulling up glass & pressing switch with my other hand. I hadn't ever worked on a cable operated window reg. so didn't know what to expect. After dismantling door liner, I found this broken part. The hex. type long nut that is fixed to the cable had broken away from the clamp for the rear of the glass.



This is what it should look like.



Some say that continued slamming of door breaks the plastic. I thought the glass may have dropped at the rear through wear in the track causing the glass to jam. Anyway it's a common problem with any car with the cable system.
A new reg. was $180 & after buying, found that the plastic part can be purchased separately on Ebay for around $25.

First thing to remove is the window switch. These pics. show the holding arrangement.




You will need a tool like this to remove the liner. [much cheaper versions are available than Stahlwille]



Door liner removal is reasonably straightforward but I will make the following suggestions.
Carefully remove plastic sheet without tearing & place side with soft adhesive uppermost without getting any dirt on it.
Place self tapping screws in separate containers with a note where they go. There are 3 different types, colour coded in different colours. You won't remember & if you put the screws in the wrong place, you will come to grief.
I unbolted the motor to remove the electrical plug, you may have more luck. The motor is rebolted onto the new regulator. There is a spacer tube that fits around one of the screws. I also sprayed some silicone into the channels before inserting the glass & taped in closed position using a couple of strips of duct tape.
It's best to check everything works freely before sticking the liner & plastic back on in case any adjustment is needed to the clamp positions on the bottom of the glass.