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Q: A/C intermintent blows hot air.

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Starts out blowing cold and some time later starts blowing hot air. Acts like the blend doors are getting changed for some reason. Diags show no fault codes.

My car has 150000 miles.
My car has an automatic transmission.

Sometimes the A/C cycling switch will cycle the A/C off like it should when the temperature reaches cycling pressures of about 24 psi. Once it cycles off and the pressures rise to the set pressure to cycle back on, it does not cycle back on and the A/C starts getting warm. The intermittent low pressure cycling switch is the most common cause of this problem and should be verified to be the problem by a qualified mechanic. Replace the cycling switch and retest the system to be cycling on and off correctly. If you need help getting this checked, have a certified professional from YourMechanic come to your location to inspect the AC system and move forward with the appropriate repair.

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