5 Main Causes Of AC Only Works When Driving

Suppose you have a car that has been used for a long time and has some minor problems. Sometimes you don’t notice or ignore them.

However, when your air conditioner is not working efficiently or producing hot air, it is bound to be something that bothers you. This condition has many causes, including the condenser fan, compressor, or coolant level.

The following article lists some details you should consider and suggests solutions when Air conditioner only works when driving.

Air Conditioner Only Works When Driving Causes

A/C Condenser Fan

A/C Condenser Fan


The A/C system that works well and stays cool is the job of the condenser fan.

Their job is to transfer heat from the indoor unit to the outdoor unit through the condenser. Therefore, the A/C condenser fan has a significant role. If they don’t work or don’t work, then you may have some problems.

The first problem you might consider is that the A/C system cannot provide the temperature you require or is not working. It happens when the vehicles are not moving, they will be at their most inefficient

Yet, if your car is on the highway or at high speed, the condenser already has enough air, so there is no need for a cooling fan. When the vehicle is stationary, there is no air circulation, and the fan plays an essential role in cooling.

The first thing you need to do is check the fan wiring and other connections. They may be loose or plugged in the wrong place. Also, check the electrical relays or their fuses.

If your fans don’t have a current problem and still won’t work, they’re probably dead. If the A/C condenser fan dies, it could be a problem with the thermostat switch or a faulty thermostat motor. It makes them not hot enough to act on the fan.


A/C Condenser Blockage

A/C Condenser Blockage


If your car is not cool when stationary and the fan is working correctly, you can consider other sources of the problem.

In addition to the Air conditioner condenser fan, you can check the condenser. They can become clogged with contact and contain too much dirt due to a lack of cleaning after a long time. As soon as you discover the problem, the first solution is to clean these parts. Cleaning can help get the air circulating again.

When the condenser is clogged, you need to clean them clean so as not to affect the entire system. If left too long, you may have to replace part or all of the A/C system.

One detail you can consider is the coil, which can get dirty due to being left uncleaned for a long time, causing clogging. Similar to condensers, you need to keep them clean, not only of dirt but also of debris from them.

These activities should happen as often as you own the vehicle. Regular vehicle maintenance can best limit the factors that cause dissatisfaction when driving.

Watch this video to find and fix this problem:

Faulty or Worn Condenser Parts

Condensers are often clogged, leading to inefficient system operation. The condensers make short rotations, the A/B systems start up continuously and are ineffective, even though they operate at total capacity.

It will cause harmful effects on parts for a long time. So then, what you need to do is replace some features or the whole system.

The condenser consists of several parts: motor, fan, switch, coil, etc. Over time, these details can become dirty or worn, which means that the condenser may not hold the same capacity as before.

Some of the activities you can do are clean parts or the entire system. Besides, you can also replace them if necessary.

You should consider repair and replacement if you encounter some errors:

  • Engine: If your machine has problems, you need to replace it. However, not every engine is suitable for your vehicle. You will need to review your old engine description for exact figures, which helps prevent unexpected errors.
  • The switch is not working correctly: You can find this detail at the store or e-commerce platform for a replacement. Switching is also effortless.
  • Like a switch, if the capacitors have problems, you can also easily find and replace them.

However, those are simple errors you encounter. Sometimes, you find more difficult bugs to fix, causing the system to stop working.

  • Condenser: This unit can become clogged with dirt or metal particles. They cause a hard-to-resolve error. In this case, you should replace the condenser, even the entire AC.
  • Coil: Replacing a piece or a part in the loop is very difficult and rarely done. Because they are time-consuming, costly, and challenging to do. What people usually do is replace the entire lock in the AC. Thus, this activity will save costs, save time and effort.

Air Conditioner Compressor

A/C Compressor


The control center of the car AC is the compressor. It will be difficult to notice the problem as soon as you encounter it because when the system is underperforming, there is more than one problem causing it.

The cooling coil is in the compressor, which means the wiring isn’t more astonishing or works more but isn’t as efficient when your car isn’t running.

That’s why auto repairs usually check the compressor first if you have this problem. A sign of a poorly performing or not working A/C compressor is that your air conditioner is not emitting cool air or producing hot air.

The cause of this error is that the system cannot cool due to insufficient or not transported refrigerant to operate.

When the vehicle stops, you can most clearly feel this is inefficient, especially when driving on highways with no outside air blowing in.

The second sign you may notice is noise. It comes from the compressor, precisely the internals. Since compressors have so many parts, it’s hard to find where they’re coming from. You should listen carefully to spot the details of the error.

At the same time, you should also try turning on the A/C switch to know when the noise is coming out. It may or may not be output while the A/C is on. If the A/C does not turn on and the noise persists, the compressor would not be the fault.

Low Coolant/Freon level

Check coolant level


Freon is also known as the coolant used in air conditioners. They help keep your engine at the right temperature. They will change depending on the weather to keep your engine running efficiently.

If the outside temperature rises high, the freon will help keep the engine cool and working correctly. At the same time, if the outside temperature gets low, the freon can keep the engine warm and at the right temperature.

Therefore, if the coolant level is insufficient, the proper temperature-keeping operation will be less effective. Your systems will also be inefficient or not, as they rely heavily on the coolant.

You may notice this problem when the car is idle or running without outside air circulating.

In addition, you can detect a fault with the clutch sound. If you turn on the air conditioner without the clutch sound, most likely the mark is due to insufficient coolant level. Because the clutch works by reading the coolant level and before that allows the compressor to pressurize this water level.

The following reason you can consider is the condenser leak, which causes the coolant level to be lower than usual. Components in the condenser are more prone to wear and cause some physical failure, such as breakage if the condenser encounters collisions when the vehicle is in traffic, not only that.

Leaking not only does not save money but also wastes money. It leads to poor performance of the air conditioner. However, it will be challenging to detect these errors.


Why is my Air Conditioner hot even when idle?

Hot AC, even when idle, is a problem not only for some typical vehicles. They occur in vehicles during use.

The leading cause of this problem is little or no vehicle maintenance.

What does the average Air conditioner repair cost?

Repair cost

Repair costs depend on your system. If you need to replace the entire system, you can expect to pay between $200 and $800.

Also, if your condenser fan has problems that need replacing, it will cost you $300 to $500. The details and costs vary widely since this is a reasonably standard error.

Some other parts have a nominal replacement cost under $300. You can consult prices in many places when making a decision.

Can I repair the Air Conditioner myself?

The answer is it shouldn’t. It would help if you did not fix problems with your air conditioner yourself. All you need to do is take your car to a professional mechanic because the air conditioner is a device that is quite difficult to deal with errors.

However, you can perform some checks on parts such as the air filter, thermostat, circuit breaker, cleaning, and air conditioner cleaning yourself.


The article has provided some notes when you encounter the error of the air conditioner not working. The problem can come from one or more details inside the AC.

You may need to do some basic cleaning and checks. However, if you can’t fix it yourself, you need to take your car to a professional. At the same time, the cost will depend on the condition of your car.

You should take your car in for regular maintenance. Not only does this keep your vehicle in good working order, but it also protects you and your family’s safety.

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