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Mazda A/C Mystery

Had my 97 Mazda Protege’s A/C diagnosed today, since I get no cool air at all. Interestingly, freon is plentiful, compressor and condensor are in great shape, no leaks in any hoses.
However, mechanic says there is a problem with the A/C Amplifier/the thermo-switch is not providing a ground signal. He also said its something between the evaporator core and the blower motor.

If anyone can help, it would be great.
P.S. the blower motor resistor is fine - I can get hot air at several different levels.

So, you’re saying the mechanic can diagnose it, but can’t fix it?

If that’s the case, find a better mechanic or take the car to a shop that specializes in automotive HVAC systems. They’re not that hard to find.

The AC amplifier is in the cars computer (ECM). It provides ground to the compressor clutch relay (therm-switch?) Start with the relay.