Yet another heater problem
 

I've done the requisite search, but this seems to be a bit different.

The wife's 300SD has a heater problem. On a trip yesterday, it wasn't very hot, so I turned the heater control to a cool temp (in ecomony mode). Later, when it started to get cool out, I set the temp to 22 and got HOT air. Kept getting hot air even after the cabin was toasty. Turned the control back to cool and still got hot air. Turned off the climate control, back on and after a minute the air got cool. Hmmm. Turned it to 20 degrees (about 50f outside) and got HOT air and kept getting it. Set the temp control to cool and still got hot. Repeated for troubleshooting sake and got the same results - always HOT air, never warm or changing. Stays cool on the max cool setting, but only a couple of degrees more on the wheel creates HOT air. Once I tried the A/C setting and got cool air, but changing back to economy, at the same setting, I got HOT air.

This car has had a super climate control for hot weather (I've had the car only through the summer) and my wife hasn't complained about the heater, but that doesn't mean it has been working - she might just turn the fan on low and open the window.

Dosen't sound like a monovalve to me, but maybe I'm wrong. Anyone have this symptom before?

Any ideas?

After the recent posts on heater problems, I seem to have fixed the one I was having. I cleaned the contacts on the monovalve connection and now the heater varies the amount of heat like it should. Thanks for the help!