I'm So glad I didn't go to that guy that was trying to charge me $135 to recharge my a/c.....after taking out my glove box and not knowing what the hell I was doing, I decided to take a simpler approach (thanks to slk230red) i went to have a look at my heater/ac valve just next to the battery behind the firewall and under the screen. I just replaced it 11/5/09 (i keep detailed records on everything i replace and the mileage). i disconnected the valve and lifted the little lever up and blew inside WALLAH! the air went straight through it. So i filled my mouth with coolant (just kidding), i used regular water and blew it through both ends with the levber up and it wasn't blocking out the flow of water. I then plugged both ends of the valve and reconnected it and m,y a/c doesn't blow hot/cold air anymore and my ac will stay cool even if i sit idle or accelerate. My question is, how long are these partsd supposed to last? Its made out of all plastic but wow, only 7 months? and i think it actually went out before then so maybe 4 months. was it a defective part? also here is a detailed link with pics on how to trouble shhot the a/c system for the 190 http://www.benzworld.org/forums/w201-190-class/1358590-troubleshooting-mercedes-benz-190-e-d.html