how to repair ac outdoor contactor


How to Repair AC Outdoor Contactor


When your AC unit stops working, one possible culprit could be a faulty outdoor contactor. The outdoor contactor is a crucial component of your air conditioning system that controls the flow of electricity to the compressor and condenser fan motor. If it malfunctions, your air conditioner may fail to start or stop working altogether. In this article, we will guide you through the process of repairing an AC outdoor contactor, helping you troubleshoot and resolve the issue to keep your home cool and comfortable.

Understanding the AC Outdoor Contactor

The outdoor contactor is responsible for coordinating the flow of electrical current to the compressor and the condenser fan motor. When the thermostat signals the need for cooling, the contactor acts as a switch, allowing the electricity to flow to the compressor and fan motor. Without a functioning contactor, your AC unit cannot run efficiently or at all. Therefore, it is crucial to troubleshoot and repair any issues with this component.

Signs of a Faulty Contactor

Before delving into the repair process, it is essential to determine whether your AC unit's contactor is the cause of the problem. Here are a few signs that indicate a faulty outdoor contactor:

1. Non-responsive unit: If your air conditioner fails to turn on, the contactor may be the culprit. A malfunctioning contactor can prevent the flow of electricity, rendering the AC unit non-responsive.

2. Continuous operation: On the other hand, if your AC unit stays continuously running without the ability to turn off, the contactor may be stuck in the closed position. This can result in excessive wear on the system and increased energy consumption.

3. Buzzing noise: A faulty contactor may produce a buzzing sound as it attempts to engage or make electrical connections. This noise indicates a potential issue with the contactor's internal components.

4. Pitting or burning marks: Visual inspection of the contactor may reveal signs of pitting or burning marks. These marks can indicate excessive heat and wear, suggesting a malfunctioning contactor.

Gathering the Necessary Tools

Before starting the repair process, gather the following tools:

1. Screwdriver set: A set of screwdrivers will be required to remove the panel and access the contactor.

2. Insulated gloves: To protect yourself from potential electrical shocks, wear rubber or insulated gloves throughout the repair process.

3. Voltage tester: A non-contact voltage tester is essential for ensuring that the power is disconnected before starting any work on the contactor.

4. Replacement contactor: If the contactor is irreparable or severely damaged, you will need a new contactor. Be sure to choose a replacement that matches the specifications of your AC unit.

Step-by-Step Repair Process

Now that we have covered the necessary tools and identified the signs of a faulty contactor, let's dive into the step-by-step repair process to get your AC unit up and running again:

1. Safety first: Before performing any work on your AC unit, ensure that the power is turned off at the breaker panel. Use the voltage tester to verify that there is no electrical current present.

2. Access the contactor: Remove the service panel to gain access to the inner components of your AC unit. Depending on your specific model, you may need to unscrew or unclip the panel.

3. Disconnect the contactor: Using the appropriate screwdriver, carefully disconnect the wires connected to the contactor. Take note of the wire connections to aid in the reinstallation process.

4. Remove the faulty contactor: Once the wires are disconnected, unscrew and remove the faulty contactor from its housing. Keep track of any screws or mounting brackets that need to be transferred to the new contactor.

5. Install the new contactor: Position the new contactor in the same location as the old one. Ensure that it is aligned correctly and securely fasten it using the screws or mounting brackets.

6. Reconnect the wires: Attach the wires to the corresponding terminals on the new contactor. Take care to connect each wire to the correct terminal according to the notes or pictures taken during the disconnection process.

7. Double-check the connections: Before closing the panel, double-check that all wire connections are secure and properly tightened. Loose connections can lead to electrical hazards and system malfunctions.

8. Restore power and test: Once you are confident that everything is properly connected and secured, restore power to the AC unit at the breaker panel. Use the thermostat to test if the repair was successful. The AC unit should now turn on and off as expected.


Repairing an AC outdoor contactor can save you a significant amount of money and discomfort. By understanding the function of the contactor and recognizing the signs of a faulty component, you can troubleshoot and resolve the issue with relative ease. Remember always to prioritize safety and gather the necessary tools before beginning the repair process. Regular maintenance and inspection of your AC unit's contactor can prevent future problems and ensure that your air conditioning system operates smoothly and efficiently for years to come.


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