I have a 2003 E500 with Automatic Climate Control. During a long trip in 70 and 60 degree weather I was not able to produce heat from the climate control.I increased the temperature to 80degrees and it still blows cold air.?! Evenwith the Air off it still blows cold air.
Is this normal?

 

Run the diagnostics program over on http://www.eclassbenz.com/node/27 and write down the values 1-8 and the error codes.Could be something as simple as a stuck duovalve.Stuck in the wrong position it is not letting water thru to provide heat.Run the tests post the results and if you want to see if it works,Give the duovalve a firm tap with the heavy end of a screw driver,dont dent it just a firm drum like tap,on both cans,the duovalve is on the passenger side engine comp.and is near the firewall looks like two small alum cans side by side.A lot of times this trick works if they are stuck.
ohlord
"GOT CODES?"
And no it's not normal