how to open up ac unit to get to contactor



Air conditioning units are an essential part of the modern household, helping us stay cool and comfortable during hot summer months. However, just like any other mechanical device, they may occasionally require maintenance or repairs. One common issue that homeowners face is having to access the contactor inside the AC unit. The contactor acts as the switch that controls the flow of electricity to the unit's compressor and fan motor. If the contactor becomes damaged or faulty, it may need to be replaced. In this article, we will guide you on how to open up your AC unit to access the contactor and carry out the necessary repairs or maintenance.

Why Accessing the Contactor is Important

The contactor is a vital component of an AC unit as it controls the electrical current flow to the compressor and fan motor. Over time, the contactor can wear out or become damaged, leading to issues like a non-responsive AC unit or a unit that fails to start. In such cases, accessing the contactor becomes crucial for diagnostics, repairs, or replacements.

Preparing for the Task

Before attempting to open up your AC unit to access the contactor, it is important to take some safety precautions. First and foremost, ensure that the power supply to the unit is turned off. This will prevent any risk of electric shock while working inside the unit. It is advisable to turn off the circuit breaker dedicated to the AC unit in your home's electrical panel.

Once the power is turned off, grab a few essential tools for the task. You will need a screwdriver, adjustable wrench, and possibly a multimeter to check the electrical connections. It's also a good idea to have some gloves and safety glasses to protect yourself during the process.

Accessing the Contactor: Step by Step

Now that you are prepared, let's dive into the step-by-step process of opening up your AC unit to access the contactor.

Step 1: Remove the Access Panel

To locate the contactor, you will need to remove the access panel on your AC unit. The access panel is typically located on the side or top of the unit and is held in place by screws. Use your screwdriver to carefully remove the screws and set them aside in a safe place. Once the screws are removed, gently pull the access panel off to expose the inner components.

Step 2: Identify the Contactor

With the access panel removed, you will now have a clear view of the AC unit's internal components. The contactor is a small rectangular or box-shaped device usually located near the center of the unit. It is typically covered by a plastic or metal protective cover. Take a moment to identify the contactor, noting its position and any electrical wires connected to it.

Step 3: Disconnect the Power

Before proceeding further, it is crucial to ensure that the power is completely disconnected from the AC unit. Even though you have already turned off the circuit breaker, it is always wise to double-check. Use your multimeter to confirm that there is no electricity running to the unit. Safety should always be your top priority during any kind of electrical work.

Step 4: Remove the Contactor Cover

Once you have confirmed that the power is disconnected, you can proceed to remove the cover protecting the contactor. Use your screwdriver or wrench, depending on the type of screws holding the cover in place. Carefully unscrew and remove the cover, being cautious not to damage any of the internal components.

Step 5: Inspect the Contactor

With the cover removed, you now have a direct view of the contactor. Take a moment to inspect it for any signs of damage, such as burned or corroded terminals. A damaged contactor may require replacement. If you suspect that the contactor is faulty, it is advisable to call a professional HVAC technician to assess the situation and carry out the necessary repairs.

Step 6: Disconnect the Wires

If you have determined that the contactor needs to be replaced, or if you are simply performing maintenance, you will need to disconnect the electrical wires attached to it. Before doing so, make a note of the wire colors and their corresponding terminals. This will help you reassemble the unit correctly once the job is completed.

Using your screwdriver or wrench, carefully loosen and remove the wires from the contactor. Take your time and ensure that each wire is disconnected without causing any damage. If necessary, label the wires to avoid confusion later on.

Step 7: Replace or Clean the Contactor

If you are replacing the contactor, simply remove it from its mounting and take it with you to a local HVAC supplier to find an exact match. Ensure that the new contactor has the same voltage rating and terminal configuration as the old one.

If you are performing maintenance, you can clean the contactor with a soft brush or compressed air. Remove any dust, dirt, or debris that may have accumulated on the contact points. Cleaning the contactor can help improve its performance and extend its lifespan.

Step 8: Reassemble and Test

Once you have replaced or cleaned the contactor, it's time to reassemble the unit. Carefully reconnect the electrical wires to their respective terminals, following the notes you made earlier. Ensure that the connections are secure and tight.

Next, replace the contactor cover and use your screwdriver or wrench to tighten the screws. Once everything is securely in place, reattach the access panel using the screws you set aside earlier.


In this article, we have discussed the importance of accessing the contactor inside your AC unit and provided a step-by-step guide to help you perform this task. Remember always to prioritize safety by turning off the power supply and using the necessary protective gear. If you are unsure or uncomfortable with any step of the process, it is best to contact a professional HVAC technician to assist you. With proper maintenance and care, your AC unit will continue to keep you cool and comfortable for years to come.


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