My minivan’s A/C only blows hot air. I added freon, but the clutch never engaged. Then I pulled the connector from the pressure switch and shorted it. I started the car and the A/C, but the clutch would not engage. Then I checked the relay and also the fuses. Both of those were good. The low side revealed 100psi on the car gauge. What is your diagnosis and what will solve this? Thanks.
I would suggest checking power and ground for the A/C compression clutch. The power is fed through the wire connector to the clutch, and it’s grounded though the body of the compressor to the engine block. If there is power and ground, then the compressor clutch has failed. If there is no power there, then you will need to follow the wiring diagram back up from the compressor, checking at multiple spots along the way. Without the compressor clutch running, the pressures on the high and low side will read the same. They only become different once the compressor is running. If you need help having this checked, a certified technician from YourMechanic will be able to come to your home or office to diagnose your A/C system and assist you with any repairs.
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