I now realize what activates the flow of hot air. A door behind the glove box.

I recently swapped out the heater hose valve as it had been leaking for over a year. I removed the throttle body and bellows for access and clamped the hose and did a quick R&R.

Also the Climate control unit had been sitting on my desk all summer asking me to try to get the AC Going again. I never did it. I have repaired and replaced this unit in my 940s a number of times.

When I went to put everything back, the heat would not blow hot. That's how I came to realize the heat door is not working. I have a working example(940B) in the driveway, so I have tested three control units. All of them activate the door in in 940B.

I did a little diagnosing of the wires at the motor and found no differences between the two cars.

I find it hard to believe the motor that activates the door just stopped working. I must be missing something. Any thoughts on this?
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89 240 wagon, 94 940, 300K, 94 940, 141K