your a/c issues might be bad duo valves(heater control valves).
The best way to ck it is to unplug the duo valves, make sure you have 12 volts at the 2 outer terminals. When you start the car and turn the a/c on you should have a ground at the center terminal. If you do that means the a/c control unit is good, probaly have bad duo valves.

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