ac compressor clutch stays engaged

AC Compressor Clutch Stays Engaged

An air conditioning (A/C) system is a valuable component in a vehicle, especially during scorching summers. The A/C compressor clutch plays a crucial role in regulating the A/C system, allowing it to engage and disengage efficiently. However, a common issue faced by some car owners is when the A/C compressor clutch stays engaged all the time, even when it should be disengaged. In this article, we will explore the causes behind this problem and how to address it effectively.

Symptoms of a Clutch That Doesn’t Disengage

When the A/C compressor clutch remains engaged continuously, several symptoms may arise. The most apparent sign is the constant spinning of the compressor, even when the A/C system is turned off. This can lead to excessive wear and tear on the A/C components, reducing their lifespan and affecting overall performance. Moreover, the A/C system may not provide adequate cooling or may freeze up due to the refrigerant’s excessive accumulation.

Causes of A/C Compressor Clutch Staying Engaged

Several factors can contribute to the A/C compressor clutch staying engaged. One common culprit is a faulty low-pressure switch. The low-pressure switch is responsible for communicating with the A/C system and signaling when the clutch should engage or disengage based on pressure readings. If the switch malfunctions, it may fail to measure pressure accurately, resulting in the clutch staying engaged all the time.

Electrical issues within the A/C system can also cause the compressor clutch to remain engaged. A damaged or shorted wire in the electrical circuit can disrupt the communication between the A/C control unit and the compressor, leading to continuous engagement.

Moreover, problems with the compressor clutch coil, such as internal shorting, can cause the clutch to remain engaged even when it shouldn’t be. Additionally, a blocked orifice tube or expansion valve can disrupt refrigerant flow, preventing the clutch from disengaging properly. Lastly, overcharged refrigerant in the system can create excessive pressure, causing the clutch to stay engaged continuously.

The Low-Pressure Switch and Its Function

The low-pressure switch is a critical component located near the A/C compressor. Its primary function is to monitor the pressure of the refrigerant in the A/C system. When the pressure drops below a certain threshold, the switch sends a signal to the A/C control unit, prompting it to engage the compressor clutch. Conversely, when the pressure rises above the specified limit, the switch signals the control unit to disengage the clutch.

Diagnosing the Issue

Diagnosing the cause of a continuously engaged A/C compressor clutch requires some troubleshooting. Using pressure gauges, an automotive technician can check the pressure readings in the A/C system to determine if they fall within the normal range. Additionally, testing the low-pressure switch for functionality is essential to identify if it is the root cause of the problem. Also, inspecting the electrical components and wires for damage or faulty connections can help pinpoint any electrical issues.

Steps to Disengage the A/C Compressor Clutch

To disengage the A/C compressor clutch, the faulty low-pressure switch must be replaced. Before replacing the switch, the refrigerant must be safely drained from the A/C system, following proper environmental protocols. It is crucial to avoid releasing refrigerant into the atmosphere, as it is harmful to the environment.

After safely draining the refrigerant, the old low-pressure switch can be unscrewed from the refrigerant canister, and the new switch can be installed in its place. Once the switch is replaced, the A/C system can be refilled with the appropriate amount of refrigerant using a refill kit from an automotive store.

Professional vs DIY Repair

While some DIY enthusiasts may attempt to diagnose and fix the continuously engaged A/C compressor clutch, seeking professional help is often the safest and most effective solution. Professional technicians have the necessary expertise and equipment to accurately diagnose the issue and perform the appropriate repairs. Additionally, A/C systems are complex, and attempting repairs without proper knowledge can lead to further damage.

Preventative Maintenance

To avoid issues with the A/C compressor clutch staying engaged, regular A/C system check-ups are essential. Professional maintenance allows for early detection of potential problems and timely repairs, preventing more significant issues in the future.

Common Mistakes to Avoid

When dealing with A/C system issues, several common mistakes should be avoided. Incorrect refrigerant charging can lead to inefficiencies and impact the A/C system’s performance. Ignoring warning signs and unusual noises can exacerbate the problem and result in costly repairs. Moreover, using cheap or low-quality replacement parts can lead to premature failures and further complications.


The A/C compressor clutch staying engaged is a common issue that can significantly impact the efficiency and longevity of the A/C system. Proper diagnosis and timely repairs are essential to ensure the A/C system functions optimally. Regular maintenance and professional check-ups help prevent such issues and maintain a comfortable driving experience throughout the hot summer months.

By addressing the problem promptly and following preventive maintenance measures, car owners can enjoy a cool and refreshing A/C system, making driving in extreme heat more comfortable and enjoyable. Remember to seek professional help whenever necessary and avoid common mistakes to keep the A/C system in top-notch condition.


While it is possible to drive with the A/C compressor clutch engaged continuously, it is not recommended. Continuous engagement puts unnecessary strain on the A/C system, potentially leading to premature wear and decreased overall performance. Driving with the A/C system turned off until the issue is fixed is a better temporary solution.

The cost of fixing a stuck A/C compressor clutch can vary depending on the vehicle make and model, as well as the severity of the problem. On average, the cost can range from $200 to $800, including parts and labor.

Attempting to manually disengage the A/C compressor clutch is not recommended, as it can lead to further damage to the A/C system or cause safety hazards. A/C system repairs should be performed by trained professionals.

If the A/C system continues to freeze up after fixing the clutch, other issues may be at play, such as improper refrigerant levels, a faulty expansion valve, or an obstructed evaporator coil. Further inspection by a professional is necessary to diagnose the root cause.

Yes, a continuously engaged A/C compressor clutch can put significant strain on the entire A/C system, leading to premature wear and potential damage to other components like the compressor, condenser, and evaporator.

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