2000 528i rear passenger window malfunction

My rear passenger window just stopped working - it made a grinding noise when it went down, and then would only come up about an inch. I could hear the mechanism work briefly, and was able to get the window partially up by pulling up on the glass while holding down the switch. Then it stopped completely...nothing from either the switch on the driver's door or the rear door...does anyone have an idea as to what has failed? I'd love to know before I take it to the shop...thanks!

Les

This power window malfunction has now happened to me twice, once on each rear window. I have a 98 528i.
First time in 2002, my non-dealer mechanic informed me that it was a broken regulator--the frame/guidewire track that upon which the window motor sends the glass up and down. It is made of plastic and breaks often. Apparetnly American cost efficiency has infected German engineering.
Had to replace both the regulator and the motor b/c they are usually sold or only inventoried as one combined piece. (Suppose you could try to recycle motor and buy just a regulator, but the wait and labor cost may not be worth it.) Or you may have a bad motor and a good regulator but the solution is the same since they are sold as one piece.

Regulator/Motor assembly part is about $200 and labor was 1-1.5 hours--total cost to me to fix wa about $400.
I have not priced it out the second time. Am considering just locking window in the closed/up position and foresaking use of that window since it is likely to happen again.

Good luck.