7 Reasons Car AC Compressor Turns On and Off (Solved)

car ac compressor turns on and off frequently, quickly, after few seconds and at few minutes and at idle

The compressor’s primary function is to move your car’s AC. The compressor ensures that the refrigerant is circulating through the air conditioning system so that cool air can move inside your car’s cabin.

Car AC Compressor Turns On and Off – Why?

Your car ac compressor turns On & Off because of inadequate refrigerant, auto climate setting, electrical issues, clogged or dirty condenser, faulty compressor, bad cooling fans, and dirty and clogged air filters.

Inadequate refrigerant

Refrigerant is the coolant that cycles through the AC system, absorbs heat, and cools down the air inside your car.

Your vehicle can lose its refrigerant over time due to leaks. It can also occur when the AC compressor remains idle for an extended period.

When this happens, the pressure drops every time you engage the AC compressor.

Consequently, the resulting low pressure turns off the AC compressor, and after some time, the pressure stabilizes again, and the compressor is engaged once more. This cycle is commonly referred to as the low-pressure cutout. The vice-versa of this cycle is known as the high-pressure cutout, and it usually occurs when your car’s AC system has too much refrigerant.

If this is the case, your car’s AC compressor will rapidly cycle on and off. Inadequate refrigerant usually indicates less coolant circulating in your car’s AC system. As a result, the AC will have difficulty cooling down your car’s interior when the temperatures rise.

If this problem isn’t fixed in good time, it will damage the compressor, which means you’ll need to replace the entire AC system.

Auto climate setting

Most modern vehicles come with an additional feature known as auto climate control. This feature automatically controls the temperature of your car’s interior based on the surroundings. While this may seem like a great feature, it has its drawbacks.

The auto climate control setting overworks the AC compressor when it comes to cooling down your car’s cabin.

Regardless of the season or surrounding temperatures, you will force the AC compressor to run at all times. This will cause the AC compressor to keep turning on and off in the long run.

Electrical issues

If you notice that the AC compressor turns on and off every time your car is under hard acceleration, it may indicate a problem with the electronic module.

This problem may occur when a section of the programming fitted into the electronic control unit (ECU) takes all extra functions that may rob power from an accelerating engine.

This power is then redirected back to the car’s engine. Therefore, if your AC compressor is turning on and off frequently, it may indicate that your car’s ECU is failing.

Clogged or dirty condenser

The main function of the condenser is to cool the refrigerant while your car is in motion. The condenser uses the airflow from outside your vehicle to complete this cooling process.

After continued use, the condenser is bound to accumulate debris and get dirty. But, when your car’s condenser accumulates too much debris, it will clog and prevent the refrigerant from cooling.

Sometimes even the partially cooled refrigerant will come out extremely hot. It results in a high-pressure cutout to prevent further damage to the AC compressor. This forces the AC compressor to cycle on and off when your vehicle is idle.

Even if the condenser isn’t clogged or dirty, it can easily sustain damage due to debris floating in. When this happens, your car will produce warm air when you want cold air. This will also lead to the complete failure of your car’s air conditioning system.

Faulty compressor

If the compressor is faulty, the refrigerant won’t circulate properly. Consequently, your car won’t receive proper cooling. A defective AC compressor will turn on and off even when your vehicle is idle.

The AC compressor becomes faulty or ineffective when you don’t drive your car as frequently as you should or when you rarely turn on the AC while driving. Going long periods without using the AC compressor will cause the AC to malfunction when you turn it on.

Bad cooling fans

The compressor connects to other AC system components, including the cooling fans. If the AC system is not cooling down your vehicle like it used to, it indicates a problem with the cooling fans. Sometimes cooling fans break because of debris floating from the road.

If the cooling fans malfunction, the AC compressor will not function effectively. It will instead turn on and off on its own accord.

Dirty or clogged cabin air filter

If your cabin air filter is dirty or clogged up with debris, it will restrict airflow to the air conditioning system. As a result, the AC compressor will be forced to keep running non-stop to cool down the cabin to your preferred temperature. This will likely cause various AC problems, including short cycling. After running constantly, the AC compressor will start turning on and off more frequently than before.

Related Post: Car AC Light Blinking/Flashing/Flickering/Turns On & OFF

Is It a Problem If the Air Conditioner Compressor Turns On and Off?

It is perfectly normal for the AC compressor to cycle on and off. For instance, you will likely set your car’s air conditioning system at a cooler temperature during a hot day. This means that the AC compressor will have to work harder to maintain cool temperatures inside the cabin.

Once temperatures decrease inside the cabin, the AC compressor will shut off for several minutes until the temperature inside the cabin changes. This cycle will repeat itself until you turn off the engine.

When Is the AC Compressor’s On and Off-Cycle a Problem?

The AC compressor’s on, and off-cycle becomes a problem if it happens too frequently. If your car’s AC compressor isn’t completing a normal cooling cycle, it indicates various issues. When the AC compressor short cycles, it causes ineffective cooling of the car’s interior and burdens the air conditioning system.

If you do not deal with the problems in good time, the internal components of the AC system will sustain damage. Another AC compressor abnormality to look out for is staying on at all times instead of turning on and off.

How Often Should a Car AC Compressor Cycle On and Off?

A healthy car AC compressor should cycle about 2-3 times an hour when the weather is hot or humid. These cycles should last about 15-20 minutes long, and they are sufficient to keep your car’s interior cool. It is normal to see higher running times if the temperature outside is higher than usual.

However, if the AC compressor cycles on and off for less than 10 minutes, it is faulty and needs immediate attention, preferably from a mechanic.

If the AC compressor inside your car turns on and off after every few seconds or stays on throughout, you should also reach out to a reliable and experienced mechanic. This way, the mechanic can inspect the AC compressor for the faults causing problems.

What to Do When the Car AC Compressor Keeps Turning On and Off

  • If low refrigerant levels cause the problem, ensure that you top it up to the optimal level as recommended by your car’s manual or by an experienced mechanic.
  • Ensure you use the car’s air conditioning system several times a month regardless of the season. This will help extend the compressor’s lifespan and prevent it from becoming inefficient due to lack of use.
  • If malfunctioning cooling fans are causing the problem, consider replacing them as the mechanic advises.
  • Visit an experienced and reliable mechanic to diagnose any electrical issues your car may have.
  • If the cabin air filter is dirty, let the mechanic inspect and clean it thoroughly. If this does not fix the problem, consider replacing the air filter.
  • If the AC compressor is short cycling due to dirty condenser coils, you can inspect and clean them thoroughly with a clean piece of cloth. Wipe everything carefully and ensure you do not leave dirt or debris. You can also use a spray cleaner to clean the condenser coils.
  • If the AC compressor is slightly damaged, get a professional mechanic to repair it. However, consider replacing it with a new one if the AC compressor has extensive damage. The average cost for replacing an AC compressor is about $500-$2500, depending on the make and model of your car. Note that an AC compressor should last for 8 to 10 years. Choosing high-quality suppliers guarantees this. Similarly, ensure you keep up with car maintenance to secure proper function and longevity.

How to Troubleshoot the Car AC Compressor Turning On and Off Every Few Seconds

  • Check the refrigerant level.
  • Check the cabin air filter and condenser coils for any debris.
  • Check the fuses and wiring to the AC compressor.
  • Turn on the AC and check for any airflow obstruction.
  • Turn on the AC and check the air’s temperature.
  • Listen and inspect the AC compressor for damage.

Also, check this video to troubleshoot the car ac compressor.

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