Window on passenger wide frequently interrupts its raising motion and goes down again. With repeated attempts the window closes eventually. It makes no funny noises at all, but operation is erratic as such. Very cheap replacement parts including the window motor are available online. I would try those. Or are they complete junk? Do I need some special tools for installation? My earlier Audi had the window mechanism mounted with some rivets. Metal was too thin to accept bolts. So I am cautious.

 

Before you go to replace the regulator, why not try this. Lower the window all the way and continue to hold the button down for 2-3 seconds. you may feel a slight click. If that is what happens then raise the window all the way and it should work properly. If you have an owner's manual look this up in it. Sometimes the windows get out of sync and this process will correct the issue.

 

+1

You will often see this procedure referred to as resetting window travel limits. It can be required after a battery swap and the symptoms are often an early warning of a failing battery.

The regulator design is the same as the one on my XK. I had to remove and refit this to change the door handle reinforcement and the procedure didn't require any special tools. Here's the X351 extract from the Parts Catalogue with an ilustration of the regulator:





If resetting the travel limits doesn't fix it, I'd definitely have the door card and inner panel off to check for loose fixings or obstruction on the channels BEFORE buying any new parts.

Graham

 

Also, as a preventive maintenance, use silicon spray on the window tracks for smooth operation. After applying on all 4, roll the windows up & down 2x. Do the same process again next year.

 

Travel limit teach-in procedure of the windows is not clearing the issue. I am aware, that touch operated windows need to learn the fully open and closed positions. But the issue with the passenger window remains. It sometimes closes without problems but at other times it needs typically 3 attempts until it closes without stopping and rolling down again.
Meanwhile I found the 3k+ page workshop manual with detailed instructions (did I mention how awesome the wealth of Information here in this forum is?).
The manual mentions a glass release lever p/n 501-114. I found the approximate dimensions of that lever and I will try to improvise something similar.

 

Could be the anti trap feature. This is designed to reverse the window lift direction if a hand or head is in the way to avoid injury. However, it can be activated if the glass is unable to move freely in the guide channels. Damaged channel(s) or misaligned glass due to loose fixings can be a cause.

Graham