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Patrick Riley
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Why Is My AC Making a Clicking Noise? A Phoenix Tech Answers

July 29, 2020

If you hear a faint click or two when your AC starts up, you probably have nothing to worry about. That’s just your thermostat signaling your system to cycle on. However, if you hear prolonged clicking and/or your AC is not cooling your home, there’s an issue with your system.

A clicking noise is usually due to an electrical issue. However, there could be a variety of other reasons that your AC is making a clicking noise, including:

  • Faulty Contactor
  • Dead Capacitor
  • Thermostat issue
  • Loose fan

Below, we’ll dive into each of these issues in a little more detail so you can get a better idea of why your AC may potentially be making a clicking noise and what you can do to fix it.

If you’d rather have a professional take a look at your AC, we’d be happy to help. We’ve been around for quite some time, so no matter why your AC is making a clicking noise, we can help. For our general AC repair pricing and process, you can check out our AC repair page.

Clicking Noise #1: Faulty contactor

Your contactor essentially plays “operator” when it comes to your AC system. Your thermostat calls for cool air, and your contactor is in charge of turning your outdoor AC unit “on.”

However, if your contactor is broken, malfunctioning or simply worn out, the message will never get from your thermostat to your outdoor AC unit, which can cause a clicking noise as the system tries to start up but can’t.

If you think you may have a bad contactor, you’ll need to reach out to a pro. Because this piece of your AC can store a high voltage, attempting to repair or replace a contactor could shock you or result in damage to your AC system.

Clicking Noise #2: Dead capacitor

The capacitor is essentially a large battery that helps “start up” your outdoor unit.

Just like any battery, over time, capacitors can lose their charge, and the clicking noise you’re hearing is usually an indication that your outdoor AC unit is trying to turn on, but can’t.

If you think that you may have a bad capacitor, you’ll need to reach out to a professional to replace it.

Clicking Noise #3: Thermostat Issue

If you hear a loud clicking noise and your system won't turn on, you're likely dealing with a thermostat issue such as a broken relay or a wiring issue.

In normal operation, you should hear a soft clicking sound when your thermostat tells your AC to turn on. That’s the sound of a relay opening to power on your AC unit. However, if the relay is broken or there's a wiring issue, the relay will continue to open and attempt to send power to your AC but fail.

Unfortunately, both of these repairs (broken relay or wiring issue) will have to be made by a professional, so if you think your thermostat is the culprit, you’ll want to reach out to a pro to come and take a look.

Clicking Noise #4: Loose Fan

If you hear a clicking noise near your outdoor AC unit, it could be a loose fan.

If your fan becomes loose for some reason, it can hit the casing of your outdoor unit when your AC is running, and create a kind of clicking or tapping noise.

If you think this is your issue, you should reach out to a professional. They will be able to take your AC unit apart and determine whether it can be tightened or if your fan blades or the entire fan need to be replaced.

Still having issues with your AC system? Reach out to Patrick Riley

If you’re stuck with one of the above issues, you’ll need a professional to come and fix it. Luckily for you, we’ve been around for quite some time, and Phoenix homeowners trust in the quality of work that we do.