how to replace ac compressor contactor


How to Replace AC Compressor Contactor

Have you been experiencing issues with your air conditioning system lately? Does it make strange noises or fail to cool your space adequately? If so, there's a high chance that your AC compressor contactor might be faulty. The contactor is an essential component of your air conditioning system that controls the flow of electricity to the compressor. Over time, it can wear out or become damaged, leading to various AC problems. In this article, we will guide you through the process of replacing the AC compressor contactor, ensuring your AC unit functions effectively once again.

The Importance of the AC Compressor Contactor

Before delving into the detailed steps of replacing the AC compressor contactor, let's understand its significance in the overall functioning of the air conditioning system. The compressor contactor acts as a switch, controlling the flow of electrical current to the compressor. When the thermostat signals the need for cooling, the contactor closes, allowing electricity to flow and activating the compressor. This, in turn, compresses the refrigerant and initiates the cooling process. Without a properly functioning contactor, your AC unit may not start, resulting in no cooling or inadequate cooling.

Gathering the Necessary Tools

Replacing the AC compressor contactor is a relatively straightforward task, provided you have the proper tools at hand. Before beginning the process, make sure to gather the following tools:

1. Screwdriver: To loosen and tighten screws during the replacement process, you will need a compatible screwdriver. Make sure it matches the size of the screws on your contactor.

2. Voltage Tester: A voltage tester is crucial for ensuring there is no electrical current present while working on the contactor. This precaution prevents the risk of electric shock.

3. Insulated Gloves: Insulated gloves provide an extra layer of protection against electric shock while working near electrical components. It is always wise to prioritize safety.

Preparing for the Replacement

Now that you have the necessary tools, it's time to prepare for the replacement process. Follow these steps to ensure a smooth transition:

1. Turn Off Power: Before starting any work related to electrical components, it is essential to turn off the power to your air conditioning system. Locate the circuit breaker that controls the AC unit and switch it off to disconnect all power supply.

2. Discharge Capacitor: The capacitor stores electrical energy even after the power is turned off. To discharge it and avoid any potential electrical shocks, use an insulated screwdriver to bridge the gap across the terminals of the capacitor.

3. Verify Power Supply: Even after turning off the circuit breaker, double-check the power supply using a voltage tester. Ensure that there is no electrical current running to the contactor before proceeding further.

Replacement Steps

Now that you have completed the necessary preparations, it's time to replace the faulty AC compressor contactor. Follow the steps outlined below:

1. Remove the Access Panel: Locate and remove the access panel on your air conditioning unit to gain access to the contactor. The location of the panel may vary depending on the make and model of your AC unit.

2. Identify and Label Wires: Before removing the wires from the contactor, it is vital to identify their positions correctly. Take a picture or use colored labels to mark the location of each wire. This step ensures proper reconnection later.

3. Disconnect Wires: Using a screwdriver, carefully loosen the screws securing the wires to the contactor. Make sure to hold the wires to prevent them from falling into tight spaces or becoming tangled.

4. Remove the Defective Contactor: Once all the wires are disconnected, unscrew the contactor from its position. Carefully remove it, making note of the orientation and position for future reference.

5. Install the New Contactor: Take the new contactor and align it with the screw holes previously occupied by the defective contactor. Insert the screws and tighten them securely to hold the new contactor in place.

6. Reconnect Wires: Referencing the picture or labels you created earlier, reconnect the wires to the respective terminals on the new contactor. Ensure they are tightly secured, but be careful not to overtighten and damage the contactor or wires.

7. Replace the Access Panel: Place the access panel back onto the air conditioning unit and secure it with the screws previously removed. Double-check that all screws are tightened appropriately.

Testing and Verifying the Replacement

With the AC compressor contactor successfully replaced, it's time to test the system and verify that it is functioning correctly. Follow these steps to ensure your AC unit is working optimally:

1. Restore Power: Turn the circuit breaker for the air conditioning system back on to restore power supply. Ensure all covers and panels are securely in place.

2. Set the Thermostat: Adjust the thermostat to the desired temperature and ensure it is in cooling mode. Listen for any abnormal sounds as the system starts up.

3. Monitor Cooling: Pay close attention to the cooling performance of your AC unit. Allow it to run for a while and assess whether it is effectively cooling your space.

4. Check Contactor Functionality: Using a voltage tester, carefully check the functionality of the new contactor. Ensure it is correctly closing and allowing current flow when the thermostat signals for cooling.


Replacing the AC compressor contactor is an essential task to ensure the smooth and efficient functioning of your air conditioning system. By following the steps outlined in this article, you can confidently replace the contactor and restore your AC unit's cooling performance. Remember to prioritize safety by turning off power, discharging the capacitor, and using appropriate gear. With these precautions in place, you can successfully replace the AC compressor contactor and enjoy a comfortably cool environment once again.


Just tell us your requirements, we can do more than you can imagine.
Send your inquiry

Send your inquiry

Choose a different language
Current language:English