Hello,

I believe that I have two separate issues:

(1) My heater & AC works when it feels like it.. You can press one of the buttons wait 5 minutes or some other random time and it works. It works for that trip as long as you don't turn it off.

(2) The heater when working at city speeds quickly blows cold at highway speeds.

Any thoughts???

Your mono valve is probably torn. If it is not then look at the in dash foam tube, it could be gone.

Dave

__________________
1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

Thanks, I will head down that path and post progress!