Why Air Conditioner Only Works When Your Car Is Moving

There is nothing funny about slowing down to wait for a friend and suddenly finding out 5 minutes later that the car is a few degrees hotter. You check your car’s cooling system, and it is not blowing chilled air as it should or worse, it has stopped working entirely.

If you find yourself in an unpleasant situation where your car air conditioner works only when your car is moving, this guide is for you.

Let’s go through the possible reasons why your ac only works when driving and how to fix it.

Why Air Conditioner Only Works When Car Is Moving?

Six main reasons why your air conditioner only works when car is moving
Main reasons why your AC only works when car is moving

1. Engine Overheat

If your AC only works when you are driving, your engine is likely overheating. Unfortunately, not everyone who owns their car knows their engine. Once your car engine temperature is not at the right level, a lot of car-related issues arise. One of these is the air conditioning malfunction. For digital gauges, the ideal engine temperature should be below 240oF is okay. It is a lot easier with analog meters. If the engine reads cold (car needs a little warming) or normal, then all is well. However, if it rises above 240oF or the analog meter tilts closer to hot than cold, your car is in a bit of trouble. Your air conditioning compressor moves air to the condenser from the radiator. Therefore, an overheating engine coupled with an already underperforming radiator or condenser can cause your air conditioning to malfunction. In that circumstance, it only cools when your vehicle is in motion.

How To Fix It

Check the cause of the engine overheats. There are numerous reasons for this occurrence: radiator issues, coolant leakage, low engine oil, and thermostat failure.

Read more: Want to read the OBD2 codes related to your AC system? My recommendation is to buy an OBD2 code reader. A cheap Bluetooth scan tool such as Bluedriver is an excellent fit.

2. Freon At Low Levels

Another reason why the air conditioner works only when your car is moving may be low freon levels. If your air conditioning system freon levels are below what is needed, your car ac will not cool properly. As a result, it only cools when your car is moving as the car is then capable of pumping the freon with ease. Once idle, your car struggles to pump freon.

How To Fix It

Refill the freon in your AC if you know the procedure. Otherwise, it is preferable to seek professional help.

3. AC Condenser Fan Is Defective

A defective AC condenser fan is a possible reason why your AC only works when driving. When your car is in motion at top speeds, the condenser does not require the fan to cool the freon. At that moment, the freon is receiving sufficient air. That is not the case when the car is idle. The condenser’s cooling fan is responsible for cooling the freon’s heat when the vehicle is in a stationary position. This task cannot be accomplished when the AC condenser fan is damaged or malfunctioning. As a result, the air conditioner does not work when your car is idle.

How To Fix It

Possible causes of a damaged ac cooling fan include:

  • Faulty fuses, Relays, and wiring: The starting point in resolving any electrical problem in your automobile is with fuses, relays, and wiring. It is essential to check for a blown fuse, short circuits, and relays.
  • Temperature sensor: If the temperature sensor is faulty, the fan will not activate.
  • Motor problems: A motor short or open circuit will prevent the motor from running, and the fan will not work.
  • Slacking blades: Where your fan blades are slacking or loose, the fan may not work correctly and will affect your car’s air conditioning as a result.

It is advisable to seek auto care experts’ help when fixing any AC condenser fan-related challenges.

4. Debris

Keep debris away from your air condenser. The presence of junk in your condenser may be a reason why your AC Once dirt obstructs the fins, your car’s cooling process will be affected. With reduced airflow, you will find that your ac only works when driving.

How To Fix It

Fixing a clogged condenser is simple – clean it! Please get rid of all the debris that may have bent the cooling system and reduced airflow, making it difficult for the car to perform when idle.

5. Open Windows And Doors

A less technical reason is due to open windows or doors. Turning down your windows when the ac is on is a waste of gas as your car will not cool as expected.

How To Fix It

Therefore, it is advisable to check that all your windows are up and your doors closed before taking any further action to rectify it.

6. Damaged Compressor

Often due to periods of prolonged disuse – particularly during winter – it is common for your car compressor to go into shock. The resultant effect is that your AC does not work as it should, or worse, releases only hot air. Your car compressor is the backbone of your air conditioning. It is responsible for the circulation of the refrigerant through the air conditioning system.

How To Fix It

Sadly, the best solution to this problem is buying a new compressor. That is why we recommend that you prevent your compressor from entering into a shock by carrying out the following instruction:

Run your air conditioning on full blast for a minimum of fifteen minutes (irrespective of the outside temperature) every three weeks.

Dan Collins Carbibles.com

This action would keep your air conditioning in perfect condition, irrespective of the season.

Bonus: Want to know the OBD2 codes related to your AC system? Search AC system OBD2 codes HERE
Video: Why Air Conditioner Only Works When Your Car Is Moving


A faulty car air conditioning is never pleasant, especially if you are in a more temperate or humid environment. However, if the major challenge you face is that your air conditioner works only if your car is moving, then these are the six most significant reasons why. It is also important to note that you may need professional help to resolve most of these causes.

Read More: 10 Best Jump Starter With Air Compressor 2021 [Review]

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.