my 2003 E500 is blowing hot air from the rear vents. has anyone else had this problem? and if so can you tell me what you did to repair it.
by Visitor in Houston, TX on July 05, 2010
The temporary work around is to raise the temperature of the rear vent to 'HI' then back down to the desired temperature. There is a heat exchanger shut off valve that needs to be replaced, can be a 1 hour DIY if you're not afraid of removing and reinstalling parts, approx $60 from dealer.
I have this same exact problem. The air blows cold at first for about the first 10 minutes in the back but then the back starts to blow really hot air yet the front vents stay cold as they should. Is the part name that I need to get from the dealer called a "heat exchanger cut off valve"?