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Q: AC compressor only engages around 40% of the time

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The AC does not always engage, a mechanic thought it was an electrical problem. Signal not reaching the compressor. When it does engage the compressor is working well

My car has 108000 miles.
My car has an automatic transmission.

This is likely due to a faulty thermostat sensor which is responsible for controlling the temperature at which the AC compressor comes on. To determine this will require a series of tests. I would recommend having an expert from YourMechanic come to your home to diagnose your compressor issue and make necessary repair.

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