Car AC Compressor Turns On and Off Rapidly – Reasons


The air conditioning system is vital in ensuring maximum comfort in a car, especially on a hot sunny day. However, its components are not immune to faults. For instance, if your car AC compressor turns on and off rapidly, it simply means something is wrong. Vehicle forums often discuss this issue and suggest that a failing A/C compressor can affect the car’s comfort due to inconsistent cooling.

Understanding the causes and solutions to this problem will help you tackle the issue before it escalates into something more complex. Some of the main reasons for your AC compressor’s short cycling have been revealed in this article.

Car ac compressor turns on and off rapidly

What is AC Compressor Cycling?

The AC compressor plays a pivotal role in a car’s air conditioning system. It is responsible for compressing the refrigerant and circulating it through the AC system. Generally, it cycles on and off to maintain the desired cabin temperature. However, rapid cycling, where the compressor switches on and off quickly, can be a sign of a malfunction, leading to decreased efficiency and increased wear on the compressor.

Causes of Car AC Compressor Turns On and Off Rapidly

Struggling with a malfunctioning AC compressor can be frustrating, especially when you can’t figure out the cause of the problem. There are several reasons why your car AC turns on and off randomly. However, some of the major causes of the problem are faulty ac compressor, low refrigerant, blocked ac condenser, clogged air filter. For example, in a Honda Civic, if the AC compressor turns on and off and emits a squelching noise, it could be due to low refrigerant levels or a problem with the timing belt connected to the compressor. These are explained below.

Low refrigerant level

Just like blood is essential to the human body, so is the refrigerant to an air conditioning system. The refrigerant is required to absorb the heat in the AC and give off cool air. However, this operation is performed in synergy with the compressor and other related components.

Meanwhile, when the refrigerant becomes low, mainly due to leaks, the circulation pressure from the compressor will drop. The low pressure cutout will automatically turn off the AC compressor and not blow cold air.

Excessive refrigerant

Too much freon in the AC is another reason why your car AC turns on and off randomly. This is because the excess refrigerant level triggers a high-pressure cutout due to the strain on the AC compressor.

When this happens, the compressor will eventually experience short cycling glitches. This challenge is usually traceable to wrongly applying a DIY AC recharge strategy, resulting in an improper refrigerant charge. You can notice smoke under the hood due to the issue.

Dirty air filter

The air filter is designed to trap dirt or debris from circulating alongside the airflow in the air conditioning system. Unfortunately, the dirt build-up can clog the unit over time, preventing the free flow of air in the AC.

When this occurs, the AC condenser coils may not receive sufficient airflow. Also, the AC compressor will be made to overwork due to the lack of airflow, resulting in random short cycling.

Clogged AC condenser

The AC condenser and compressor synergize in the operations that release cold air into a car’s interior. However, the condenser relies on the airflow from outside the vehicle to complete the AC cooling process of blowing cold air. 

Unfortunately, the air comes with dirt or debris, which can clog the condenser over time. The blocked condenser will not be able to properly cool the Freon to release cold air due to accumulated dirt or debris. This automatically puts more strain on the AC alongside the compressor, resulting in short cycling.

Defective AC compressor

The AC compressor is the heart of the air conditioning system. Unfortunately, this component doesn’t last forever, as it may become faulty over time due to wear and tear from constant usage.

On the other hand, lack of usage for a long time can also affect the compressor. A bad compressor will not be able to circulate refrigerant properly. When this happens, the compressor will likely experience a rapid on and off cutout.

How to Fix AC Compressor Cycling Problems

If you’re experiencing an AC compressor cycling problem, ensure to diagnose the actual cause of the problem and fix it immediately. Meanwhile, the following are possible solutions to a short cycling compressor.

Recharge the AC

Performing an AC refrigerant recharge will help to rectify your car’s AC compressor short cycling problem if lack of Freon is the initial cause of the problem. However, consult an expert HVAC technician to handle the recharge process for a perfect job.

Remove excess refrigerant

If you discover that too much Freon in your car’s AC is responsible for the compressor turning on and off rapidly, removing the excess Freon will fix this issue. Again, DIYers with extensive ideas about the HVAC system can handle this; otherwise, call an auto technician immediately.

Clean up/replace the air filter

Since the cabin air filter is susceptible to being clogged with dirt or debris over time, cleaning the component will help rectify the compressor issue if the dirty air filter is the problem. Meanwhile, if the filter is badly clogged, ensure to replace the component to avoid returning to the same issue quickly.

Unclog/replace AC condenser

If a clogged or dirty condenser is responsible for the AC compressor’s cycling problem, carefully clean the component to unclog it. Where necessary, kindly replace the parts as soon as possible.

Repair/replace the faulty compressor

Lastly, if you’re sure that every other component is intact and a defective compressor is the actual cause of the short cycling, please replace the compressor at the earliest.

If the fault is minor, you may want to contact an expert auto mechanic to fix it immediately. However, replacing the part will ultimately get rid of any other hidden faults that may surface in the future.

FAQs

Why is my car’s AC compressor short cycling?

A blocked or clogged air filter is one of the common reasons why your car’s AC compressor is short cycling. The air filter is expected to clean air inflow into the HVAC system by trapping dirt, particulates, or contaminants. However, when the component becomes dirty, it will prevent proper airflow.

Unfortunately, this occurrence can cause the AC cooling coil to freeze and further affect the AC compressor, resulting in short cycling. If you’re experiencing this challenge, ensure to consult a professional HVAC auto technician.

Is it normal for AC compressor to turn on and off?

The AC compressor does not always work; hence, it is okay for the component to turn on and off periodically. However, this is expected to happen within a cycling period of 15 – 20 minutes or 2 to 3 times within an hour.

Therefore, if your car AC compressor goes on and off sporadically without maintaining the expected cycling time frame, it is a sign that something could be wrong with the air conditioning system. You should check it out immediately.

Why does my AC compressor stop after a few seconds?

The AC compressor is built to respond to the operations of other related components within the HVAC system. For instance, the compressor’s low-pressure control device is designed to shut off the parts when the AC is low on refrigerant.

Also, overheating may be responsible for an AC compressor stopping after a few seconds. So, if your car’s air conditioner’s compressor stops working after a short time, inspect the system to find out what could be wrong.

How do I test my car compressor?

bad compressor test

The following step-by-step procedures will help you test your car’s AC compressor to know whether it’s working correctly or not.

Step 1: Locate the compressor by tracing it through the drive belt that powers the component. Meanwhile, ensure that the engine is off while performing this exercise. The compressor usually has two hoses connected to it.

Step 2: Turn on the car’s engine, put on the AC, and turn on recirculation. After that, step out to check whether the compressor clutch pulley is spinning. If the pulley is spinning, the compressor is okay. Besides, you may want to check out this video for visual guidance.

What is the most common cause of compressor failure?

Excessive or low refrigerant level is the most common cause of car AC compressor failure. Too much Freon in a car’s AC will automatically strain the compressor, causing it to fail. This is a result of an incorrect AC recharge process.

Meanwhile, due to the low Freon level, the compressor will also be subjected to a more difficult task of pumping refrigerant through the air conditioning system. A refrigerant leak usually cause the low Freon level.

Conclusion

Undoubtedly, the air conditioning system is a delicate component in a vehicle. Therefore, it must be handled as such. So, if your car AC compressor turns on and off rapidly, inspect the system thoroughly to identify the problem.

Once you spot the root cause of the problem, do not hesitate to fix it as soon as possible. However, delaying the repair of some faulty components can cause the problem to escalate into a more costly repair. On the other hand, regular maintenance checks on your car’s A/C system, including the belt’s condition and refrigerant levels, ensure everything runs smoothly without uncomfortable noises or interruptions.

Solomon Osuagwu

Osuagwu Solomon is a vetted auto mechanic with over ten years of experience in the garage and five years of experience as a service writer. He prides himself in writing accurate information on professional repair guides, DIY repair guides, buyer’s guides, comparisons, and car reviews. If he’s not in his repair garage, he’s writing automotive blogs to help car owners and fellow mechanics to troubleshoot and proffer solutions to several car problems.

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