Like the other complaint about the same knob it probably has to do with being to close to the cup holder!! I have 2 friend that have a 2011 and 2012 and that knob does not work either! It's used to change the radio station and scroll through the Navigation Gps so it's pretty important. Benz should recall it and fix it for free because it's a bad part!!!! Otherwise I love my C350!!!!

Radio/Navigation knob on center console of car is inoperable. It sits in close proximity to the cup holders so it is very susceptible to liquids getting into the system if you drink anything in the car. I'm not sure this was the cause of the failure but it wouldn't surprise me. Estimated cost of repair from the dealer was $500. Vehicle should not put electronic knobs, dials, or switches right next to cup holders in my opinion.