how to fix ac contactor


How to Fix AC Contactor


When your air conditioner fails, it can be incredibly frustrating. One common culprit behind AC malfunctions is a faulty or damaged contactor. The AC contactor is a vital component that controls the flow of electricity to the various components of your air conditioner. Fortunately, most contactor issues can be resolved with some basic troubleshooting and repair techniques. In this article, we will guide you through the process of fixing an AC contactor step by step. By following these instructions, you can save money on professional repairs and ensure the efficient functioning of your air conditioning system.

Symptoms of a Defective AC Contactor

A defective AC contactor can manifest itself in various ways. It is important to identify these symptoms to determine if the contactor is indeed the cause of your AC issues. Here are some common signs that your AC contactor needs fixing:

1. AC Not Cooling Properly:

If your air conditioner does not cool the room efficiently or blows warm air, it might indicate a faulty contactor. This occurs when the contactor fails to engage properly, preventing the compressor or fan motor from receiving power. As a result, the airflow might be limited, leading to inadequate cooling.

2. No Power to AC Unit:

When the contactor fails, it can cut off the power supply to the entire AC unit. If you notice that your air conditioner is completely unresponsive, it could be due to a faulty contactor. Before assuming it is the contactor, ensure that the power supply is functioning correctly and there are no issues with the circuit breaker.

3. Constant Clicking Noise:

A rapid clicking or chattering sound coming from the AC unit is often an indication of a failing contactor. This noise occurs when the contactor rapidly tries to engage and disengage, resulting in a disruptive clicking sound. If you notice this symptom, it is essential to address the issue promptly to avoid further damage to the contactor.

4. Stuck Contactor:

In some cases, the AC contactor might become stuck in the closed or open position. A stuck contactor can cause the AC unit to continuously run or fail to start at all. This can result in energy wastage and potential damage to other components of the air conditioner if left unresolved.

5. Burnt or Pitted Contacts:

Upon inspection, if you notice that the contacts of the AC contactor are burnt, melted, or pitted, it indicates a severe problem. This damage can occur due to electrical arcing, excessive heat, or age. In such cases, replacing the contactor is usually the best solution.

Step-by-Step Guide to Fix AC Contactor

Now that we have identified the symptoms of a defective AC contactor, let's move on to the step-by-step guide on how to fix it.

1. Turn off the Power:

Before working on any electrical component, it is crucial to turn off the power supply to ensure your safety. Locate the main electrical disconnect switch for your air conditioner and switch it off. Additionally, you should also turn off the circuit breaker that controls the AC unit.

2. Remove the Air Conditioner Panel Cover:

Next, remove the panel cover of your air conditioning unit. It is typically located near the condenser or outdoor unit. Use a screwdriver or the appropriate tool to remove the screws holding the cover in place. Keep the screws in a safe place to avoid losing them.

3. Locate the AC Contactor:

Once the panel cover is removed, locate the AC contactor. It is a box-shaped component with multiple wires running to and from it. The contactor is usually situated near the compressor and has two halves that make or break electrical connections.

4. Inspect the Contactor:

Carefully inspect the contactor for any visible damage, such as burnt or pitted contacts. Pay attention to loose or disconnected wires as well. Cleaning the contactor with a soft brush to remove dirt and debris is also recommended. If the damage is severe or the contacts are beyond repair, it is best to replace the contactor entirely.

5. Test the Voltage:

Using a multimeter set to the voltage testing mode, check the voltage at the contactor. Turn on the power supply and verify if voltage is present at the input terminals. If there is no voltage, it indicates a different issue with the electrical supply rather than a faulty contactor.

6. Disconnect Wires:

Before removing any wires, take a picture or label them to ensure you can reconnect them correctly later. Gently disconnect the wires connected to the contactor. It is essential to remember their original positions and connections.

7. Remove the Defective Contactor:

Using a screwdriver or the appropriate tool, carefully unscrew the contactor from its mounting bracket. Once detached, inspect the contactor again for any signs of damage or wear. If replacement is necessary, purchase a new contactor that matches the specifications of the old one.

8. Install the New Contactor:

Position the new contactor in the mounting bracket and secure it with screws. Reconnect the wires to their appropriate terminals as per your earlier documentation or reference. Make sure the connections are tight and secure.

9. Reassemble and Test:

Carefully reassemble the air conditioner panel cover and screw it back in place. Once everything is securely assembled, turn on the power supply to the air conditioning unit. Test the functionality by adjusting the temperature settings and observing if the AC is cooling effectively.


A faulty AC contactor can cause significant discomfort during hot summer months. By recognizing the symptoms of a defective contactor and following the step-by-step guide provided, you can easily fix the issue yourself. Remember to always prioritize your safety and turn off the power before working on any electrical components. Cleaning, inspecting, and replacing the contactor, if necessary, are the main steps to ensure a properly functioning air conditioning system. By taking the time to troubleshoot and repair your AC contactor, you can save money and enjoy the comfort of a cool and efficient home.


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