Why is My AC Unit Clicking But Not Turning On—Or Repeatedly Clicking?

March 26th, 2023

Any strange sounds coming from your home’s cooling system are likely to cause some concern—but what if the AC unit is clicking repeatedly after you turn it on? Or clicking and not cooling your home?

This could be for a variety of reasons from a loose part in the compressor to electrical, fan, thermostat or other mechanical issues. It’s important to identify the nature of the clicking noises and then do a little AC troubleshooting before calling for professional HVAC repairs.

Of course, clicking noises and other common problems with your home’s cooling system can be avoided with regular AC maintenance, which ensures that you and your family stay cool all year round.

Let’s delve a little deeper into AC clicking noises when turned on:

What causes AC clicking noises when turned on?


Most of the time, a relatively new AC unit that is installed professionally and well-maintained will run relatively silently with little more than a soothing hum or whirr—certainly no unusual clicking noises other than an initial loud click on starting up.

If the AC unit clicks but doesn’t turn on or makes repeated clicking noises during cooling, there may be issues with certain components, such as the compressor, capacitor, fan, thermostat or other mechanical/electrical parts. Generally speaking, these noises are a sign that maintenance has been neglected or your unit is old and has been working too hard.

When troubleshooting clicking noises, first identify where the noises are coming from and whether it’s periodic or continuous. It could point to a relatively innocuous problem or a more serious issue depending on what you find. Regardless, don’t attempt AC repairs yourself because it requires handling potentially dangerous elements, such as refrigerant and electrical setups.

Instead, contact the AC repair professionals at One Way Air. We are well used to resolving all types of AC noise issues.

Types of AC clicking noises

Did you think that a clicking noise was simply a clicking noise? No! When it comes to AC units, there are several different types of clicking noises!

AC professionals will usually recognize a particular type of clicking and associate it with a particular component. Let’s take a look at the main types of clicking that can affect AC units:

Non-stop clicking while running

If you turn your AC on and it starts to cool but makes constant loudish clicking noises, it usually points to a problem with the fan that helps to circulate cool air throughout the rooms in your home.

This can be an alarming sound but the problem is not usually too serious. Minor fan repairs or blade replacement may be required. However, if you neglect the problem and force your AC to consistently work too hard to create the necessary airflow, more serious damage can be caused to the unit.


Clicking after starting and shutting down

If your AC unit clicks when you turn it on and it begins the cooling cycle but then clicking noises gradually subside until you turn the AC off again (when the noises return), it’s likely a problem with the relay switch that controls the compressor or the motor or fan.

Again, professional repairs or replacement may be required sooner rather than later to prevent wider damage to your home’s cooling system.

Clicking but not turning on the cooling cycle

Sometimes, an AC unit will emit a loud click as the AC tries to turn on. This usually points to a problem with the capacitor, control board or thermostat, which all need to communicate with each other for effective cooling.

If the unit clicks repeatedly until turned off manually at the thermostat, the controls might be working but another part is malfunctioning—which will require deeper troubleshooting from an AC professional.

Clicking from the outdoor AC unit

The main outdoor AC unit is the compressor, which squeezes refrigerant and raises its pressure and temperature to increase the AC’s energy efficiency.

If the compressor unit is making a clicking noise after the AC is turned on, check to see if there are vibrations from within it. Sometimes, to fix AC compressor clicking noises just requires tightening of bolts or the removal of leaves and debris around the compressor unit.


Sometimes, too, a gurgling noise accompanies the clicking, which could mean a problem with the refrigerant line.

Clicking noises with other AC problems

Sometimes, clicking noises are heard but, otherwise, the AC seems to be working fine. AC clicking sounds should never be ignored even if your air conditioning seems to be cooling your home effectively.

When there are other problems with your air conditioning unit—like cycling on and off too frequently, excessive ice buildup on the coils or water leaks—the need for urgent attention from AC professionals is even greater before your home’s cooling system packs up entirely.

The main reasons for AC clicking noises

Remember, when an AC unit starts up, it clicks once. This is the thermostat sending a signal to the capacitors to start the cooling cycle. After this, there should be no clicking noises coming from the unit—just a soothing hum and an occasional whirr.

We’ve covered the different types of clicking noises and some of the reasons why they are made. Following is a quick summary of the main reasons why your AC could be keeping you awake with unusual clicking:

Loose compressor parts

The most common reason for clicks coming from outside of the home is loose compressor bolts or refrigerant tubing. This could get worse if not fixed but is generally a relatively easy fix for trained HVAC technicians.


Electrical problems

An air conditioning unit that clicks constantly but won’t turn on is most likely suffering from an electrical issue. A faulty capacitor or a problem with the wiring are the main culprits in these cases.

Capacitor issues mean that the thermostat cannot properly communicate with the electrical system in the AC unit.

Fan unit issues

An obstructed fan inside the AC unit or a fan with a bent blade could also cause your AC clicking noises. Perhaps a stick or large piece of debris got caught in the vent, causing the fan to click every time it strikes it or a fan blade keeps hitting another part of the unit repeatedly.

Older AC units or those that have not been serviced for a while are most susceptible to fan problems.

Malfunctioning thermostat

AC units with older thermostats may also experience strange clicking noises. Thermostats can wear out and become unreliable, sending the wrong signals to the cooling system. Regular checks should be conducted as part of an overall air conditioning maintenance plan. 

An experienced HVAC technician will troubleshoot whether the problem originates from the thermostat and if so, how to fix it.

Other mechanical issues

Air conditioning units are complex systems incorporating mechanical parts, refrigerant, and electric signals.

A range of mechanical issues other than loose compressor parts of faulty fan units can affect the AC. This is particularly true as units age and become susceptible to wear and tear issues that cause clicking noises.

If none of the above reasons pinpoint the cause of the clicking, check the piston, valve, and belt to see if they need repair of replacement. Again, an experienced HVAC technician can troubleshoot the issue and get your AC back up and running.

How to fix AC clicking issues in SWFL…

AC units are a significant cost for Florida homeowners and are essential not only for cooling but also for controlling humidity and general air quality/comfort levels in the home.

Protecting such an important investment with regular AC tune-ups should be a no-brainer. Any major issues will be flagged during service calls and, if necessary, repaired.

If clicking noises develop, don’t leave the issue to potentially cause serious damage to your AC system. Troubleshoot it if you can and contact an AC professional to diagnose and fix it.

If you’re in SWFL and have a problem with AC clicking noises or any other issue with your cooling system, contact One Way Air to arrange a full inspection and fix.

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Still have questions about your next air conditioner? Let us help you choose an air conditioner you’ll be excited for.

Need A Free Estimate?

Still have questions about your next air conditioner? Let us help you choose an air conditioner you’ll be excited for.

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