AC Compressor Not Cycling: Quick Fixes and Troubleshooting Tips

It’s a hot summer day and you rely on your air conditioning to save you from the unbearable heat. But, what if your AC compressor is not cycling as it should?

This is a common issue that many households face, leaving them uncomfortable and frustrated. To address this issue, it’s essential to first understand the role of the AC compressor in your cooling system.

In this article, you will come across some valuable troubleshooting tips to fix this issue.

AC Compressor Not Cycling

What Does the AC Compressor Do?

The AC compressor is a crucial component that circulates refrigerant throughout your air conditioning system. It compresses the refrigerant into a high-pressure gas before sending it to the condenser.

When the compressor is functioning properly, the system will efficiently cool your home, providing you with a comfortable living environment.

However, when the compressor doesn’t cycle correctly, the refrigerant may not properly pass through the system, leading to insufficient cooling.

Understanding AC Compressor Cycling

AC compressor cycling refers to the process of the compressor turning on and off as part of the cooling cycle.

To help you better understand AC compressor cycling, let’s go through some brief explanations and examples.

When your AC is working correctly, the compressor will cycle on and off to maintain the set room temperature.

This consistent cycling ensures that your home stays comfortable, and your AC system doesn’t experience additional stress.

However, if your AC compressor is not cycling, it could indicate potential issues with your air conditioning system.

There are several reasons for your AC compressor not cycling. These include:

  • Refrigerant leak
  • Dirty or clogged coils
  • Thermostat malfunction

To diagnose and address common AC compressor cycling issues, you can follow these steps:

  1. Check the Thermostat: Ensure your thermostat is set correctly, with a comfortable temperature and functioning batteries. If there’s a problem, consider replacing or repairing the thermostat.
  2. Inspect Refrigerant Levels: Low refrigerant levels can cause the compressor not to cycle. If you suspect a leak, call a professional to check and refill the refrigerant.
  3. Clean the Coils: Dirty or clogged coils can reduce your AC’s efficiency, so make sure to clean them to improve the compressor’s cycling.

Maintaining your AC system, including the compressor, is essential. Regular cleaning, proper installation, and sizing can help prevent short cycling and other issues.

Common Causes for AC Compressor Not Cycling

Check out the common reasons that can lead to the issue:

Refrigerant Issues

Refrigerant plays a crucial role in the functioning of your AC system. If there’s a leak or insufficient refrigerant, it can prevent the compressor from cycling.

Low refrigerant levels lead to low pressure on the low side and high pressure on the high side. To fix this, check for leaks and refill the refrigerant if necessary.

Thermostat Problems

A faulty thermostat may fail to signal the compressor to cycle on and off. Check your thermostat settings and ensure it’s functioning correctly. If it’s faulty, replace the thermostat to rectify the issue.

Pressure Switch Faults

The pressure switch helps regulate your AC system’s pressure. If it’s not working properly, your compressor may not cycle correctly. Inspect the pressure switch for wear and replace it if necessary.

Coil and Fan Concerns

The condenser coil and fan play a significant role in maintaining optimal pressure for the compressor to function.

Dirty coils or a malfunctioning fan can lead to issues with the AC compressor cycling. Clean your condenser coil and check the fan for any wear or damage to solve the problem.

How to Diagnose the Issue?

Diagnosing AC compressor cycling issues can be a relatively simple process if you know what to look for. To get started, you’ll need a few tools such as a gauge set to measure refrigerant pressures accurately.

Make sure to put on safety gear and follow the manufacturer’s instructions for your specific AC unit.

Check the system behavior

First, observe your AC system’s behavior. Take note of any unusual noises or inconsistent cooling patterns. Pay attention to whether the compressor is turning on and off frequently or not running at all.

Inspect the controls and wiring

Next, inspect the controls and wiring connections in your AC system. Poorly connected or damaged wires might be the cause of short cycling. In some cases, a faulty thermostat can also lead to cycling issues.

Check the refrigerant pressure

To check the refrigerant pressure in your AC system, use a gauge set. Low pressure might indicate a leak, while high pressure could mean a blockage in the system. Keep an eye on both the high side and low side pressures as you diagnose the problem.

Here are some common causes and solutions to compressor cycling issues:

  • Refrigerant Leak: Inspect for any visible leaks and consider using a leak detector to pinpoint the problem. Repair the leak and recharge the system, if needed.
  • Dirty or Clogged Coils: Clean the coils with a coil cleaner or a gentle brush. Ensure proper airflow for efficient cooling.
  • Faulty Thermostat: Test the thermostat and replace it if necessary.

By following these steps and understanding the potential causes of AC compressor cycling problems, you’ll be well on your way to a cooler and more comfortable living space.

Dealing with Compressor Short Cycles

Short cycling occurs when your air conditioner’s compressor frequently turns on and off during its cooling cycle. This can cause decreased efficiency and increased wear on the entire system.

Let’s discuss a few common causes and solutions.

Refrigerant leaks

Refrigerant leaks can lead to short-cycling. If refrigerant levels are low, the compressor may turn off due to insufficient pressure. In this case, you should contact a technician to check for leaks and refill the refrigerant if necessary.

Dirty air filters

Dirty air filters may also cause compressor short cycling. Restricted airflow can lead to a frozen evaporator coil, which forces your compressor to turn on and off frequently. Regularly check your filters and replace them when they become dirty.

Thermostat issues

A thermostat issue can cause short cycling. If your thermostat is located near a heat source, it can misread the temperature, causing the compressor to turn on and off constantly. Relocating the thermostat to a more accurate location can resolve this issue.

To prevent short cycling, you may consider the following solutions:

  • Regular maintenance: Schedule routine checkups to maintain proper system performance.
  • Correct sizing: Ensure your air conditioner is the right size for your home. An oversized unit may short cycle, while an undersized one will struggle to keep up.

Following these tips can help keep your air conditioner operating efficiently and avoid the potential issues caused by short cycling.

Dealing with Refrigerant Leaks

Refrigerant leaks in your AC compressor can be problematic, but don’t worry, you can handle it with a few simple steps.

First, identify the signs of a refrigerant leak. These may include:

  • Higher than usual electric bills
  • Poor cooling performance

Once you have identified a potential refrigerant leak, you can proceed with the following actions:

Locate the leak:  Use a refrigerant leak detector to trace your AC system lines, paying close attention to connections and seals.

Repair or replace: Depending on the severity of the leak, you may either repair it using a proper sealant or replace the damaged component.

Recharge the system: After fixing the leak, you should recharge your AC system with the specified refrigerant. Remember to follow the manufacturer’s guidelines for the correct amount of refrigerant.

Finally, monitor your AC system’s performance after fixing the leak. Also, take preventive measures such as routine maintenance to minimize the chances of refrigerant leaks in the future.

Regular Maintenance and Prevention

Regular maintenance and prevention are key to avoiding AC compressor problems and ensuring your AC runs smoothly. By following these steps, you can protect your AC unit and potentially avoid costly compressor replacement.

  • Clean and replace air filters regularly: Dirty, clogged air filters restrict airflow and can hinder your system’s efficiency. Remember to clean or replace your air filter every 1-3 months, depending on use and environment.
  • Schedule maintenance checks: Regularly scheduled maintenance with an HVAC company helps detect any issues and keeps your system in top condition. Aim for a check-up at least once a year, ideally before the cooling season starts.

For example, during a maintenance check, a technician can:

  • Inspect and clean the coils to avoid excess pressure on the compressor.
  • Check and adjust refrigerant levels to prevent leaks and ensure efficient cooling.
  • Inspect and lubricate moving parts, including the compressor, to reduce potential wear and tear.

Besides, routine maintenance involves:

  • Monitoring and optimizing refrigerant levels: Ensuring proper refrigerant levels is critical in preventing AC compressor issues. Too much or too little refrigerant can cause your compressor to work harder, leading to a potential breakdown.
  • Keeping the outdoor unit clean: Regularly check the outdoor unit for debris, such as leaves and dirt, and clean it to maintain proper airflow and avoid pressure on the compressor.

Following these preventive measures and monitoring your the performance of your AC can save you from expensive AC compressor replacement and ensure a comfortable environment in your home.

Replacing Your AC Compressor

When you realize that your air conditioner compressor is not cycling, it could be due to a faulty compressor clutch or the need for a compressor replacement.

Here’s a brief guide to help you through the process.

First, inspect the compressor clutch to ensure it’s working properly. Turn off your engine and try turning the clutch manually. If it’s sticking or not disengaging, that might be the issue.

If you find that the problem lies in the compressor, it’s time for a replacement. Replacing an AC compressor generally takes about one to two hours, and the time needed to evacuate and recharge your system.

When selecting a new compressor, consider the following features:

  • Compatibility with your vehicle’s make and model
  • Warranty provided by the manufacturer
  • Overall build quality to ensure durability

Before starting the replacement process, prepare the necessary tools and materials, which may include:

  • Wrenches
  • Socket set
  • Pliers
  • AC manifold gauge set
  • Refrigerant recovery machine
  • Vacuum pump
  • New compressor and refrigerant

Once everything is ready, follow these general steps:

  1. Safely discharge the refrigerant from your AC system using a recovery machine.
  2. Remove the belts, hoses, and electrical connections from the old compressor.
  3. Unbolt and remove the faulty compressor from the vehicle.
  4. Install the new compressor, making sure to correctly connect all hoses, belts, and electrical connections.
  5. Evacuate the system using a vacuum pump, ensuring it reaches a suitable level of vacuum.
  6. Recharge your AC system with the appropriate amount and type of refrigerant.

Remember, it’s always recommended to refer to your vehicle’s service manual for specific instructions and safety precautions.

Addressing Vacuum and Pressure Concerns

When dealing with an AC compressor not cycling issue, it is essential to understand vacuum and pressure concerns. There are two critical pressure readings: low side pressure and high side pressure.

Low Side Pressure refers to the pressure on the suction side of the compressor. To diagnose cycling issues, you need to monitor the low side pressure during operation. For a properly functioning system, low side pressure should be around 30 PSI.

High Side Pressure refers to the pressure on the discharge side of the compressor. Monitoring high side pressure can also indicate potential problems. Ideal high side pressure reading is around 150 PSI.

When checking vacuum and pressure concerns, keep the following tips in mind:

  • Inspect for leaks in your system, as they may cause improper pressure cycling
  • Ensure proper refrigerant levels to maintain the correct balance between low and high side pressures
  • Check dirty or clogged coils which can lead to improper cycling

By properly understanding vacuum and pressure concerns in an AC compressor, you can diagnose and address the issues more effectively.

Keeping track of low side and high side pressures will help you maintain your AC system and ensure optimal performance.

Dealing With a Clogged Air Filter

A clogged air filter can cause your AC compressor to stop cycling. To resolve this issue, follow these friendly suggestions.

Step 1: Check your air filter.
You should examine your air filter at least once a month. If it’s dirty or clogged, replace it with a new one.

Step 2: Maintain regular filter changes.
Set a reminder to change your air filter according to the manufacturer’s guidelines. It’s usually every 1-3 months, depending on the filter’s specifications.

Step 3: Clean around your AC unit.
Make sure that the area surrounding your AC unit is clear of debris and dust. This helps prevent clogging and improves your system’s overall efficiency.

By addressing a clogged air filter, you can improve your AC compressor’s cycling and overall performance. Remember to be proactive in your system’s maintenance for optimal results.

Understanding the Role of Airflow

Airflow plays an essential role in your air conditioner’s performance. When there is proper airflow, the AC compressor cycles as it should, ensuring smooth operation.

One common cause for an AC compressor not cycling is a blocked or restricted airflow. This can result from dirty air filters, clogged coils, or a malfunctioning fan.

To maintain optimal airflow, you should regularly clean or replace your air filters. Here are some of the common issues that bad air filters can cause.

  • Dirty air filters: Over time, filters accumulate dust, dirt, and debris, affecting the airflow. Make sure to clean or replace air filters every one to three months, depending on usage.
  • Clogged coils: The evaporator and condenser coils can also become dirty, affecting the heat exchange process.
  • Malfunctioning fan: If the fan is not working correctly, the airflow will be insufficient. Inspect the fan for any obstructions or mechanical issues.

Proper airflow ensures that the exchanged heat is dissipated effectively, allowing the system to maintain the desired temperature.

If you’re experiencing issues with your AC compressor not cycling, addressing potential airflow problems can help resolve the issue and improve your air conditioner’s performance.

What to Do When Your AC Compressor is Not Cycling

If you suspect a problem with your AC capacitor, follow these steps:

  1. Turn off the power to your air conditioning system.
  2. Inspect the capacitor for any visible damage, such as swelling, leaking, or burn marks.
  3. If you’re comfortable working with electrical components, use a multimeter to test the capacitor’s charge. Compare the readings to the capacitor’s rated specifications.
  4. If the capacitor is damaged or not within the specified range, replace it with a new one of the same specifications.
  5. Restore power to your air conditioning system and observe if the compressor starts cycling correctly.

If you’re unsure about working with electrical components or if the problem persists after replacing the capacitor, it is best to consult a professional HVAC technician for assistance.


Ensuring proper AC compressor cycling is essential for maintaining a comfortable indoor environment during hot summer days. The AC compressor plays a pivotal role in cooling your home by efficiently circulating refrigerant.

When cycling issues arise, common culprits include refrigerant leaks, thermostat malfunctions, dirty coils, and pressure switch faults. Diagnosing these issues requires careful observation, maintenance checks, and monitoring pressure levels.

Regular maintenance, clean air filters, and addressing airflow problems can prevent compressor short cycling and increase system longevity. When necessary, replacing a faulty compressor or fixing refrigerant leaks are crucial steps to ensure optimal cooling performance.

By understanding and addressing these issues, you can enjoy a consistently cool and comfortable living space throughout the hot months.

Frequently Asked Questions

Why isn’t my AC compressor spinning?

There are several reasons why your AC compressor might not be spinning.

One common cause is electrical issues, such as a blown fuse, tripped circuit breaker, or faulty capacitor. These problems can prevent the compressor from receiving the power it needs to function correctly.

Mechanical issues, such as a damaged or seized bearing, can also prevent the compressor from spinning.

How do I fix a clutch that won’t engage?

First, check if your AC system has sufficient refrigerant, as low levels can prevent the clutch from engaging.

If the issue persists, inspect the clutch coil and wiring for damage or disconnections. If the coil and wiring are in good condition, the problem might be a faulty clutch or a damaged compressor.

Why won’t AC compressor engage after recharge?

If your AC compressor doesn’t engage after a recharge, it could be due to an overcharged system or a clogged orifice tube, which restricts refrigerant flow.

A malfunctioning pressure switch or electrical issues, such as a loose connection or blown fuse, can also prevent the compressor from engaging.

What causes low pressure in AC compressor?

Low pressure in an AC compressor can be caused by:

  • A refrigerant leak in the system
  • A clogged or failing expansion valve or orifice tube
  • A malfunctioning pressure switch
  • An overcharged system

It’s crucial to identify and fix the cause to prevent damage to your AC system.

How can I reset my AC compressor?

To reset your AC compressor, follow these steps:

  1. Turn off the AC unit by switching off the thermostat.
  2. Locate the circuit breaker for your AC system and turn it off.
  3. Wait for about 30 minutes to allow the system to reset itself.
  4. Turn the circuit breaker back on and switch the thermostat back to the cooling mode.

How do I fix an AC compressor that stays on when it’s off?

If your AC compressor stays on when it’s supposed to be off, the issue might be caused by a faulty thermostat, a damaged relay switch, or a short circuit in the system’s wiring. Try replacing the thermostat to see if it solves the issue.

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Sean Mendez

Hi, I am Sean, a self-confessed petrolhead. I live in Boise, Idaho with a busy family of four and our energetic Labrador retriever. Thank you for visiting my website. You can find my email on the contact page.

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