Ok the beast is running really good except the heat is killing me. My air does not work, but the Heat (it is winter here) cannot be controlled. I turn it on and off to regulate. Does the A/C have to be working in order to get the Climate control to work? I did overall the heater control valve last year and I marked all the settings and positions of the gears, and it is working as I can hear the motor running when I shut off the car, but I don't know if this is a part of the control that regulates the heat. Does anybody have a calibration manual for the feedback pot on the heater control valve? I have the troubleshooting guide that I was faxed last year, but it does not include the calibration of the system.

PeterG



79 300SD

PeterG,

Sounds like the valve that regulates the hot water flow to the heater is stuck open.

AC does not have to work to have the heat control function to work. The AC in my '80 300SD does not work but the heat is still automatically controlled.

P E H

PEH
Sorry to get back to you so late.
Is this the motor operated valve that sits on the passenger fire/ fender area? I rebuilt this and the motor and gearing runs perfect. The only thing I may have disturbed is a feedback pot inside that housing. That is were the calibration question came from. Is there another valve that I am not aware of?


PeterG