AC Blowing Warm Air?

If your car’s air conditioning (AC) is blowing warm air, there might be an issue with the radiator cooling fans or another part in the AC system. Follow the steps in this article and video to find out if it’s the cooling fans and see our other tips to help you diagnose the problem.

Why Is My Car’s AC Blowing Warm Air?

1A Auto mechanic reviewing how a bad radiator cooling fan can cause your car's AC to blow warm air

Your car’s AC is likely blowing warm air because there’s a problem with a part in the AC system. This could vary from bad cooling fans to a bad AC condenser.

Why Do I Need Radiator Fans for My AC to Work?

An AC condenser that on many vehicles can be found in front of the radiator. It needs airflow to cool the refrigerant down that’s circulating throughout the AC system. Radiator fans increase the air flow coming from the front of the vehicle, and if they’re defective the AC condenser won’t cool down as much as needed.

More on how to inspect the AC condenser

Symptoms of a Bad Cooling Fan

Groaning Noise from the Cooling Fan

The bearings on the radiator cooling fan can fail and make a groaning sound. There may also be an issue with the impeller.

To tell if the sound is with the fan or somewhere else in the engine, lift the hood, turn the engine on, and try to listen for the sound in the engine compartment. If it sounds like it’s coming from the front of the vehicle near the cooling fans, it’s likely one of them.

Momentarily, with the engine running you can remove the fan’s fuse. This will cut the motor off, and if it coincidentally cuts off the noise, you’ll know it’s from the fan.  

Damaged or Broken Impeller

The impeller may have fallen off balance or has damage like cracking. There may also be a problem like an object getting stuck in the impeller.

Check the fan for any signs of cracking or debris like sticks or rocks. If you find debris, disconnect the battery before touching the fan to remove any debris. This will keep the fan from turning on automatically.

You’ll still want to check how well the cooling fan functions after removing the debris, since it could have strained the motor.

Cooling Fans Not Working

The cooling fans may have a weak motor that reduces airflow or cause the fans to not work at all.

To tell if the motor is weak, listen for airflow. You won’t hear a lot of airflow from the front of the vehicle with a weak cooling fan motor. Leave the car running for around 10 minutes and make sure other parts are on and working fine, like the AC system. If the fans are working, you’ll hear loud and excessive airflow from the front of the car.

If the fans aren’t working at all, they won’t turn on with the car running. They should turn on fairly shortly after the AC has been turned on.

Problem with the Radiator Cooling Fan Circuit

The cooling fan circuit has two wires for power and ground. The relays and fuses command it on. Check the fuses for power, and make sure the relays are working.

More on how to check fuses

Read more on how to check relays

More Parts to Check for a Car AC Blowing Warm Air

If the AC in your car is not blowing cold air or you’re having another problem with the AC system, check out these articles and videos for help diagnosing more AC system parts

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AC Blowing Warm Air - Diagnose Radiator Cooling Fans - 1A Auto
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AC Blowing Warm Air - Diagnose Radiator Cooling Fans - 1A Auto
Find out how to diagnose and fix a car AC blowing warm air with these tips. Learn if the radiator cooling fans are the cause or another part with the expert mechanics at 1A Auto
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1A Auto
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