Skip the auto shop - Our mechanics make house calls

Q: Air conditioner blowing hot air. Then fan was running low then sped up to high.

asked by on

Hi there. This morning while driving to work, the air conditioner in my car was blowing hot air. Then as I neared work the fan suddenly dropped in speed then immediately sped up again. On my way home it was still blowing hot air. I left to go to auto zone, (who were no help at all) and while I was parked there after getting gas and turning off the car, all of a sudden the air started blowing cool; not cold, but cool. Of course. It's been doing this off and on very sporadically lately. I live in AZ and it is still in the high 90's. I appreciate any help you can give me. Thanks in advance.

My car has 79000 miles.
My car has an automatic transmission.

Hi there. It sounds like you have a low refrigerant charge; your AC system has a low charge. This is usually caused by a leak in the system. This low state of charge can cause insufficient cooling, thus the hot or cool air and not cold air is coming out of the vents. The fan running low then speeding up is normal as the AC system is being used; the high speed fan is what cools the refrigerant in the system. I believe you may have a leak in your AC system that needs to be checked. YourMechanic has several qualified technicians that can perform an AC system inspection to properly diagnose the concern at the comfort of your home or office.

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

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  • Home
  • Questions
  • Air conditioner blowing hot air. Then fan was running low then sped up to high.

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: Some a/c fans aren't blowing air

It sounds like your mode door actuator may have failed. The mode door actuator is responsible for controlling the mode door. The mode door is a door inside your dash that will open and close to certain points to guide...

Q: Dead battery. Jumping for every start. Replaced radiator flange and now car started no prob

The radiator is not related to vehicle starting. The only relevant possibility would be if you replaced a sheet metal component that holds the radiator that may have also had a vehicle ground wire attached to it. If the vehicle...

Q: Key fob won't unlock doors

Hi. If your FOB is not unlocking the doors, then the battery in the FOB may be bad. I would either replace the battery or try a spare FOB if you have one. If the battery does not help, then...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.