Looks like the temp senser that is located behind the center dash vents is bad. I checked it this afternoon and it is very, very flaky. The only way to get a reading on it is to push on the terminals hard (and then it read 8 Megohms). Otherwise it is an open circuit, which the way I understand the schematic, should make it open up the monovalve when the temp thumbwheel is anywhere but at minimum setting. It will be getting replaced.

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Jim