why is my ac not spinning contactor


Why Is My AC Not Spinning Contactor?

As the sweltering summer heat rolls in, your air conditioner becomes a vital appliance in ensuring a comfortable living environment. However, when your AC unit fails to function as expected, it can leave you feeling frustrated and uncomfortable. One common issue that homeowners encounter is when the AC contactor fails to spin. This malfunction can result in warm air blowing out of the vents, causing significant discomfort. In this article, we will explore why your AC contactor may not be spinning and what steps you can take to troubleshoot and resolve the issue.

What is an AC Contactor?

Before we delve into the potential reasons behind a non-spinning AC contactor, it is important to understand what a contactor is and its role in the air conditioning system. An AC contactor is an electromechanical device that acts as a switch, allowing the flow of electricity between the main power source and various components of the HVAC system. It consists of a coil and contacts that open and close when an electrical signal is received.

When your thermostat calls for cool air, it sends a signal to the contactor, initiating the flow of electricity to the compressor and condenser fan motor. The compressor is responsible for pressurizing the refrigerant, while the condenser fan motor circulates air across the condenser coils to release heat. If the contactor fails to spin, it disrupts this crucial process, resulting in an ineffective cooling system.

Common Causes of a Non-Spinning AC Contactor

There can be several reasons why your AC contactor is not spinning. Let's explore some of the most common causes:

Faulty Contactor Coil

A faulty contactor coil is one of the primary culprits behind a non-spinning AC contactor. Over time, the coil can wear out due to constant usage or exposure to extreme temperature fluctuations. If the coil becomes damaged, it will struggle to generate a magnetic field strong enough to activate the contacts. As a result, the contactor will fail to engage, preventing the flow of electricity to the compressor and fan motor. Replacing the contactor coil is usually the best solution in this situation.

Defective Contact Points

The contact points of the AC contactor can become pitted or corroded over time, obstructing the flow of electricity. This can prevent the contactor from engaging properly, causing it to remain in a stationary position. Inspecting the contact points for signs of damage or buildup is crucial. If you notice any abnormalities, gently clean or replace them as necessary. Regular maintenance can also help prevent this issue from occurring.

Power Supply Issues

A disrupted power supply can prevent the contactor from functioning correctly. In some cases, a power surge or voltage fluctuation can cause the contactor to become stuck in either the open or closed position. Additionally, loose electrical connections can impede the flow of electricity to the contactor, leading to its failure to spin. Ensuring that the power supply is stable and all electrical connections are secure is essential to preventing power supply-related issues.

Defective Start Capacitor

The start capacitor provides an extra boost of power to help kickstart the compressor when your AC unit turns on. If the start capacitor is faulty, it may not provide enough power to initiate the contactor's movement. As a result, the contactor will remain stationary, preventing the compressor and fan motor from receiving electricity. Testing the start capacitor with a multimeter and replacing it if necessary can resolve this issue.

Failed Control Board

The control board acts as the brain of your air conditioning system, controlling various functions and relaying signals to different components. If the control board malfunctions, it may fail to send the necessary electrical signals to the contactor, causing it to remain stationary. A professional HVAC technician should inspect and replace the control board if it is determined to be the underlying cause of the issue.


When your AC contactor fails to spin, it can significantly impact the performance of your air conditioning system. By understanding the potential causes behind this issue, you can take the necessary steps to troubleshoot and rectify the problem. Remember to always prioritize safety and consult a professional HVAC technician if you are unsure or uncomfortable performing any troubleshooting tasks. Regular maintenance and prompt repairs can help ensure an efficient and reliable cooling system that keeps your home comfortable all summer long.


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