A fw weeks ago I ran a thread regarding the now to be called DuoValve in my 1987/300SE Euro. After I replaced the inserts and when I still got unwanted heat I thought I might have a valve leak, which I did not. As the problem is still here and the CD is not much help with a pre 1988 Euro climate control, I write again hoping someone out there knows the Euro system and can help me.
What I now get is ample heat when I want it BUT intermittent heat when I do not call for it. I have a hunch it is something electrical in nature, but might be wrong. When calling for heat and turning the temp dial selectors to the white & red zones, I get the click sound from the valves as they engage.( there is no click when the valves disengage. Somehow gradual release feels right. Is it?)
If I turn the dial down to blue I may or may not curb the heat coming into the cabin. A possible clue comes from the dial selectors. When turning them up I sometimes hear a whiny sound that recycles - as if something is failing to connect, yet trying again and again. Almost like what a vaccum element might sound like or a potentiometer. This is a guessing game (not good) and frustrating because if mine were a fully automatic acc climate control, from reading the archives the next thing I would look into would be the Heater Core Temp Sensor. In truth, I do not even know if my car has one. I want to rule out the aux water pump, because I do get heat and there is no loss of coolant underneath either. Is this the right assumption?
hoping guidance is near...

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