heat control in 1985 300D
 

I cannot control the heat in my 300D. On the defrost mode it blows only hot air, in other modes some minimal control of tempature. Is this a defective climate control unit or something else.

Pilot

RE: heat control in 1985 300D
 

I got most of the following info from Henry Schuman, et al at: http://www.schumanautomotive.com/for...splay.php?f=10

It could be the monovalve which is under the hood on the passenger side of the firewall. To check the valve, unplug it at the top, solder a couple of wires to a 9v battery and touch them to the monovalve. Keep a hand on the monovalve. If you feel it clicking on and off, the valve is probably ok. If you can't feel it, Henry Schuman has the best price I can find for the valve kit.

It's easy to replace. Simply remove the 2 common/slotted screws, take out the top, and pull to remove the valve. Then merely slide the new valve in, replace the top, screw in the 2 slotted screws, and Voila! it's done.

If it's not the valve, go to Schuman's site for more detailed info...