Both rear windows failed with different symptoms
 

I have a 2009 clk 350 coupe. When I bought the car the driver side rear window was already not working, now the passenger side has failed.

Driver side window motor is working but window will not go up or down, sounds almost like crunching glass during operation.

Passenger side window motor is working. The window will go down regardless of hitting up or down.

I believe it is likely the regulator on the driver door but some peoples opinions/previous findings would be appreciated to help diagnose and resolve the issues.

Seems like this car runs strong but has anything running off a switch is failing fast...

I'm guessing both regulators are bad, just failing with different symptoms. There's an eBay kit for fixing it that a few forum members have used. .

I order the kit for both windows. Cost me $30. I did pull apart the passenger side today and the cable was bound up and wrapped around the spindle in a total mess. I have to say, this job is a bit more or a ***** than i thought but does not seem as bad on the coupe. When the parts come in I may create a DIY video since this seems to be a fairly common issue. Also, thank you for your help