The rear passenger window regulator on my A4 has a habit of going almost closed then goes back down to opened position. With a bit of coaxing, I can get the window closed again. But, now the driver's window is jamming at the halfway up point and when I hold the switch in the 'up' position, it clunks a few times and doesn't go up. After a few attempts, I can get it closed but I am afraid one of these times it's going to stick 'open'...and it's January. Anybody have some wisdom to share?

 

Spray some silicone lube into the window channels. The window has pinch protection and is supposed to stop or reverse direction if there's something in the way. Dirt/dust buildup in the channels can make the window behave like that. After spraying, hold the buttons in the full down and full up positions for 10 secs or so to help the electronics relearn the up/down locations.