Skip the auto shop - Our mechanics make house calls

Q: A/C intermintent blows hot air.

asked by on

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.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: transmission

This could be a lack of vacuum or potentially a bad shift solenoid. Most modern transmissions operate on vacuum actuated controls and solenoids both of which commonly fail at times which will cause the lack of or intermittent shifting problem...

Q: Car overheated and hose ripped

hi. If you have a hose that has failed, then that would have caused a serious loss of coolant. This will definitely cause the engine to overheat. The hose needs to be replaced so that the engine can be checked...

Q: Car Electrical Issues

Hello, thank you for writing in. When facing electrical issues, diagnosis can be lengthy. The starting and running issue may be an issue with the ignition switch. If it is not holding the key to the "Run" position, the engine...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...