I had a similar problem on mine a couple of years ago. just turned out to be a cable clamp broke and let one of the cables move over enough to get caught under the window. It would only roll down about an inch or two before getting caught. took a little trial and error because there isn't much clearance between the cable and window but I managed to use a zip tie to reattach the cable to the door frame. I've heard several people with this same issue so I guess it must be a fairly common problem.