PeachParts Mercedes-Benz Forum - View Single Post - No "Gradient" Temp w/Climate Control on '82 300D

Richard Wooldridge · #12 06-02-2007, 02:35 AM

Brian- Sure, I'll be happy to. I will make up a little vacuum diagram and take some pictures of what I have along with the part numbers of the stuff involved tomorrow, and post it all. I have a feeling that lots of auxiliary water pump failures are being attributed to the Monovalve in error. My setup eliminates the problem altogether. I got the idea from the Unwired Tools digital servo kit that I installed in my '79 Mercedes 450SL, they use the same setup to control the heater water flow, getting the control signal from the electronics they provide. Basically, the signal that feeds the monovalve is just wired to the 12v solenoid on the vacuum switchover valve, and vacuum is applied to the heater valve through the solenoid. I found it necessary to provide a "leak" to the heater valve side so the valve could return to the open position, and did this by means of a three way connector with a piece of wire stuck in the third hole, ala the original ACII setup in my '79. (I actually installed this in my '82 380SL.) As I said, I'll come up with some pix and a diagram which should make it all very clear.