Why Does My Car Air Conditioner Keep Turning On And Off?

car AC turns on and off randomly

A long drive in hot weather is not a particularly pleasant experience on its own. And there is no way it will become any better when a faulty A/C is thrown in a mix. Besides being annoying, short frequent work cycles put a struggle on the unit and reduce its lifetime.

It is very important to repair a broken car’s air conditioning, and the first step of it is to determine the reason behind its malfunction. To help you make this first important step, here are the most widespread issues because of which a car A/C turns on and off randomly.

10 Reasons Why Car Air Conditioner Keeps Turning On and Off

Unfortunately, since an air conditioning system is a complex device with many components, there can be plenty of reasons why a car A/C keeps turning on and off again. We believe that a reasonable and effective method to distinguish what is wrong begins with those that are easier to diagnose, so the following list will go from easy problems to complex ones.

1. Clogged Air Filters

The air sucked in from the front of the car first passes through an air filter. Its goal is to catch small pieces of dirt, dust, and debris so they don’t build up on the condenser, which cools the freon used by the unit.

If this filter is not maintained and changed regularly, it will get clogged and restrict the airflow. This eventually causes the condenser to overheat and fail, making the A/C turn on and off repeatedly.

2. Dirt on Inner Parts

While one reason why the freon cannot cool is a clogged filter, another is a build-up forming directly on the components. A dirty condenser or A/C compressor cannot effectively lose heat and easily reach temperatures that drive the whole system unworkable. The said components take some time to cool down, and because of that, the car air conditioner turns on and off frequently.

3. Blown A/C Fuse

A blown fuse is fairly common but also an easily fixable reason why your car’s A/C kicks on and off while driving. To figure out whether it is the case, check it by locating a fuse box in your car and finding the right fuse using a scheme in a car manual. Pull it out with an included tool to see if it is burned or test it with a multimeter.

4. Leaking Freon

Refrigerating gasses, such as freon, are responsible for removing the heat and transporting it into the outer environment. After leaking for a long time, the amount of refrigerant may become insufficient, making the whole unit malfunction.

This is a serious issue that can permanently damage multiple components of the system. To get rid of the problem, you should bring your car to the auto repair shop.

5. Cooling Fan Malfunction

If an air conditioning has turned off by itself in the middle of a car trip, it can be because one of the cooling fans doesn’t work. There are numerous reasons for it to break down, both mechanical and electrical. To effectively solve this problem, we suggest you ask for the help of a professional car mechanic.

6. Torn Air Conditioning Belt

This problem can only happen in older cars with a separate A/C belt. The belt drives the compressor, and if it breaks due to deterioration, the A/C will work unstable and then fail. Modern cars use serpentine belts, which bring to movement multiple devices at once, including an alternator.

7. Faulty Compressor

The compressor creates pressure in the valves and tubes of an A/C unit, moving freon across them. As time goes by, the wear and tear make it less effective in moving refrigerant around. If your A/C shuts off after a few seconds of work, it may be the issue.

8. Clogged Condenser

This is a serious problem. The condenser removes heat from both A/C and the power unit. It can cause the A/C to turn on and off repeatedly. A clear indicator of a problem is when an engine overheats in traffic when the weather is hot and an A/C is on. A clogged condenser can’t effectively cool both the engine and the air cooling system.

9. Problems With Relay

If everything above seems to be fine, but the car A/C turns on and off randomly due to some undiscovered reason, a relay can be probably a guilty one.

A relay is an electronic device that can receive certain signals and turn the device on or off. It gets triggered when the car interior gets too hot and turns the A/C on for a certain time. In some cases, like after a short circuit, it will get triggered constantly for no reason and make an A/C switch on and off rapidly.

10. Bad Blend Door Actuator

A blend door actuator is a component that regulates airflow temperature by adjusting how much cooled air is added into the airflow. Any weird sounds that accompany the A/C’s work may indicate that there is something wrong with it. Those sounds include squeaking, rattling, clicking, or knocking.

This is yet another component that can make air conditioning suddenly stop working. In addition, its malfunction drives climate control useless because the actual temperature does not correspond with the settings. The broken blend door actuator needs to be replaced by an auto repair station as soon as possible.

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Final Word

Here are the ten reasons that are usually to blame for a faulty car air conditioner. To properly diagnose it, start with the easy problems and move down the list to the more complex ones.

In many cases, a simple clogged filter is responsible for this, and no serious diagnosis is needed. Ignoring problems with an A/C unit can lead to serious damage as issues remain unnoticed. If the cause of the issue is hard to find or fix, consult a professional repair service.