I have a 2015 VW Polo and the right rear power window is making a weird noise on the way up. It rolls down normally and the speed at which it rolls up and down is unaffected as far as I can tell. Here's a video
All other windows are fine. The car was driven in quite a bit of rain for the last couple of days. The dealer wants to open up the door card and check. I'm wondering if anyone can pinpoint the problematic component and/or suggest an easy DIY fix?