Air Conditioner Only Works When Car Is Moving – 6 Possible Reasons!

Recently, you bought a new stylish car with an excellent ac unit. But why air conditioner only works when the car is moving? Start the car, turn on the air conditioning system, and get inside. Ahh, the cooling sensation inside the car! But all of a sudden, you realize the a/c stops when the engine is off.

Actually, air from the exterior of the vehicle will pass through the condenser when you drive. Even without the fan, it helps to keep it cooler. Unfortunately, since the fan is not functioning, the condenser cannot be cooled when you are still and since there is no airflow. Sometimes it happens due to a low coolant level or maybe faulty parts.

However, let’s have a look at the possible issues behind the ac not working while it’s parked. Stay here to troubleshoot the issues with us.  

How a Car Air Conditioner Works

ac only works when car is moving
  1. Car ac actually does the two special jobs, and they are through a low-pressure and high-pressure stage.
  2. The refrigerant used in a vehicle’s air conditioning system is switched between a liquid and a gas form to work properly. 
  3. It allows the system to produce cold, dry air by absorbing heat and moisture from the car.
  4. The majority of auto air conditioners are driven by the engine via the drive belt. For example, the alternator, the headlights, and the compressor for the air conditioner are all powered by this.
  5. Then, the refrigerant will be compressed into the gas by the compressor. It enters the condenser after being changed into a high-temperature, high-pressure gas.
  6. After that, the refrigerant loses heat in the condenser and becomes liquid where the liquid is taken into an orifice tube or expansion valve.
  7. The refrigerant drops in temperature as it transitions back to a gas at the expansion valve.
  8. The accumulator, or dryer, dries the refrigerant by absorbing moisture.
  9. The evaporator is the last stop for the refrigerant. You have a blower fan to blow air through the evaporator core.
  10. Now, only cold air flows past the evaporator and enters your automobile through the vents.

Read Also: Subaru Outback headlight problems

6-Possible Reasons Why My Car’s AC Only Works When Moving 

ac stops working when driving

Clogged Radiator or Condenser

There is a possibility that the condenser cannot compress the refrigerant when the debris is obstructing it. The air conditioning system might still become blocked even though it is set up in a closed loop.

Because the condensers are typically located at the front of the vehicle, they might miss out on protection, and eventually, they become more vulnerable to harm from flying road debris.

The condenser is the core part of your vehicle where parts like the motor, switch, fan, and coil are located. Simply, all the parts that become dirty and worn out will tell you that the condenser is not available to keep the same capability to offer good performance.

When you miss cleaning the condenser for a long time, it becomes clogged with dirt and debris. Also, the blocked condenser can cause short cycling or rotating. To remove the obstruction and keep the engine cool, flush the radiator. Ensure that there are no traces of dirt, dust, or other obstructions inside the AC to cause the clogged compressor.

Faulty Radiator

An air conditioner that isn’t working is caused by a radiator that’s broken down, and an overheated engine is a culprit. This is a key indicator that your car’s a/c operates when it is going since the engine assists the a/c unit in operating.

Overheating and other engine problems are possibly caused by a broken sensor and a clogged radiator. This issue arises when the cooling system is neglected or the radiator is packed with outdated coolant. Corrosion and dirt are attracted to the old coolant, which can cause the radiator to get obstructed. As a result, be sure to protect it against damage or overheating.

Broken Condenser Fan

You’ll also see that even though the a/c is cooling the car, the fan is having issues. Exterior air is responsible for it. Generally, the condenser fan is required to disperse the heat from the condenser.

Unfortunately, if the fan isn’t running, the refrigerant won’t cool down enough to reach the evaporator. Most likely, the temperature is between 195 and 220 degrees Fahrenheit.

A broken fan, a blown fuse, a bad temperature sensor, a malfunctioning fan control module, and occasionally a stuck engine thermostat impact the condenser fan. As a result of these problems, the engine coolant cannot reach the ideal temperature.

The first thing you should check for when looking into any electrical problems with your car is faulty cables and relays. Check the wiring for the vehicles for loose or corroded links, short circuits, and open control systems. You can ensure the fan is dead if there are situations where the fan socket appears to be receiving enough current.

Turn on your air conditioner and adjust the blower to its highest level to fix the issue. This will turn on the fan. Most car repairs for condenser fans typically cost between $300 and $425.

Related control module: How to reset transfer case control module?

Low level of Freon or Cooler

Freon, often known as coolant, is used in air conditioners to regulate temperatures and keep engines working smoothly. Therefore, the proper temperature-keeping operation will be less effective if the coolant level is insufficient. As they significantly rely on the coolant, your systems will either be ineffective or not.

Most likely, the clutch sound will indicate a problem. The possibility of a condenser leak resulting in a lower-than-normal coolant level exists. You may also notice ice accumulation around the AC unit or the AC compressor switching on and off more frequently than usual. As a result, you must recharge the AC’s freon.

Engine Overheat Issue

If the engine overheats and the radiator and condenser malfunction, the air conditioning system may be harmed. We frequently forget to check the engine’s condition after a car trip. The ideal temperature for a car engine is, formally, less than 240°F (116°C).

The warmer temperatures will affect your car’s air conditioning because the temperature of the refrigerant and other AC system components may rise. Anomalies or spikes in temperature are red flags that the car’s engine is in jeopardy. But you should call a mechanic to fix it.

Can I Fix the Air Compressor Issue By Myself?

Costs might range from $800 to $3,000 depending on the size of the unit and a few other criteria. A professional should typically replace a compressor. However, if you have good technical skills, you can complete this task yourself at home. You can also save quite a bit of money by doing the work yourself. You’re good to go if you know how to fix an air conditioner.

My Car Air Conditioner Only Works Sometimes

When you notice the ac is working but sometimes it’s not, make sure all the vents are open and the thermostat is set properly to ensure cool air. If none of these is the issue, then check the air filter. You won’t receive any airflow if it’s blocked with dirt or other material or if there are any broken parts inside. All these reasons disturb your AC ability to work properly.

Intermittent cooling is another problem, which can occasionally be brought on by the parts of your car’s AC unit freezing up. Usually, an iced-over condenser is to blame for the situation. You will have to wait until the ice melts since an evaporator covered in ice cannot cool the air.

Why Does My AC Only Get Cold When I Drive?

car ac takes a while to get cold

Your air conditioner may be producing cold air at high speeds for one of two reasons. One possibility is that your condenser fan or fans are ineffective or so worn out that they cannot spin quickly enough to circulate adequate air through the condenser. The refrigerant won’t get cold enough if there isn’t enough airflow since the condenser needs airflow to remove heat from the refrigerant.

See more: Car ac takes a while to get cold

How Much Does It Cost to Fix My Car’s A/C?

Replacing or fixing the car compressor is a wise choice. The most common problem is low freon, which can be fixed for less than $20 or around that when you add the freon yourself.

Replace the compressor, the receiver, or the dryer, and flush the system if the compressor malfunctions where you notice metal debris is distributed throughout the system. This might cost approximately $1200. However, installing central air conditioning normally costs between $3,815 and $7,498 and the average cost is $5,657.

How Do I Maintain My AC?

  1. Professional maintenance is recommended.
  2. Replace your air filter once a month.
  3. A condensate drain check is necessary.
  4. In central systems, monitor the correct duct leakage.
  5. Check the evaporation coil’s airflow.
  6. Ensure the refrigerant level.
  7. You can use a leak detector to check for refrigerant leakage.
  8. Oiling engines and inspecting belts for wear and tightness is necessary.
  9. Find the thermostat’s accuracy.
  10. Capture the refrigerant that has to be removed from the system.
  11. Check the proper electric control sequence and ensure that the heating and cooling systems cannot operate concurrently.
  12. Examine electrical terminals, tighten connections, clean them, and add a non-conductive coating.


1. Why does the AC in a car work better when the car is driving instead of parking?

Since a car’s cooling system relies on motion, when the vehicle is parked, an electrical fan circulates external air through the radiator to generate motion and keep the engine coolant flowing.
When you are driving and the engine is running more quickly, the ac will operate well and much better. The better the system can cool, the quicker the AC compressor operates.

2. Why does my AC stop blowing cold when I stop?

When the refrigerant level is low, the air conditioner typically stops blowing cold air. Furthermore, there is a chance of internal leakage, a clogged air filter, or a compressor issue that will stop the air conditioning unit from producing a cool environment inside the car.

3. Why does my car’s air conditioner only blow cold air while driving at higher speeds?

If there isn’t enough airflow, the refrigerant won’t become cold sufficiently since the condenser needs airflow to remove the heat from the refrigerant. Good airflow results from driving at 50 mph.

4. How do I know if my condenser is clogged?

A clogged condenser may give off various warning signs, such as loud and strange noises coming from the unit or a fall in cooling efficiency. It frequently occurs when a fluid has gone through a good amount of condensation.


So, we have successfully mentioned all the possible reasons of Air Conditioner Only Works When Car Is Moving. Usually, we see that the car ac only works when there is no clogged radiator, low freon level, engine overheating, or broken condenser fan issues. Make sure you maintain all of the parts.

Additionally, we shared how to maintain your ac for better performance. Anyway, if you benefited from the article, leave your precious comment below and wait until we come up with informative content about automobiles again. Till then, enjoy the ride!