Updated at: 26-09-2022 - By: Sienna Lewis

The heart of your house is your HVAC system. It protects your house from the bitter cold of winter. Your air conditioner helps keep your home cool throughout the sweltering summer months.

People are used to hearing their HVAC systems turn on and off, no matter what time of year it is. Unusual noises, on the other hand, can draw your attention to the possibility that anything is wrong with your air conditioner.

If your air conditioner’s fan continues to spin nonstop, it may be trying to alert you something is wrong with the system.

When the HVAC system is functioning properly, the fan turns on and off automatically. An air conditioner fan that is constantly running is a sign that there is a problem with the unit.

Why does your AC fan persist on running, and what can you do to fix the problem?

Why  Does The Fan Keep Running On Your Air Conditioner?

My air conditioner’s fan won’t stop operating for the following reasons.

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Reason #1. The fan is set to “ON” instead of “AUTO”

Your air conditioner’s fan will continue to run if it has been set to ON. As a result, the fan will keep running even if the air conditioner’s cooling component is switched off.

To fix this problem, turn your air conditioner to AUTO mode. To keep your home cool, you need to use both the fan and the AC’s cooling system in tandem.

When the cooling system is active, the fan will only run if it is set to AUTO. It will shut off on its own once it has determined the optimal temperature for the room. It may be one of the following if you’ve already set it to AUTO and are still experiencing problems.

Reason #2. The AC is incompatible with the thermostat setting because it’s undersized

The air conditioner will not operate as well as it should since it is too small. When the thermostat is set too high, it will keep running and finally turn on the fan.

Excessively hot weather has the same effect. Temperatures will be difficult to decrease or chill with the air conditioner’s cooling mechanism. As a result, it will take an unusually lengthy time to achieve the temperature you set.

If you have any doubts that this is the cause of your air conditioner’s problems, try turning it down by 5 to 10 degrees. If your air conditioner automatically shuts down, it is too tiny for your home.

An AC that is too small will have a difficult time keeping you cool, especially if the outside temperature is too high. As a result, the fan will have to run nonstop. The best course of action is to call a professional or replace your air conditioner if you are experiencing this issue.

Reason #3. There is a problem with your thermostat

If your thermostat is unable to accurately measure your home’s temperature. No matter how hard you try, the fan will always turn on.

If the temperature in your house is lower than what you set on the thermostat, you have a malfunctioning thermostat. You must either replace the thermostat or call an AC professional to address this problem.

Reason #4. Malfunctioning relay switch

When the air conditioner is switched on, the fan should come on. If the fan does not operate as expected, the relay switch is most likely faulty.

If the relay switch fails, the thermostat’s temperature setting will not be conveyed to the fan. Fans will continue to run even when thermostats aren’t communicating with them.

Reason #5. Short circuit

Another possibility is a short circuit. Due to the short circuit, it will be hard to distinguish between on and off signals.

If your AC has already been turned off and there is a short circuit, the fan will continue to run even though the command has been ignored. Exactly like the other tips above, have it checked out by an air conditioning specialist.

What Are The Reasons The Fan On Your Air Conditioner Keeps Running?

If the fan on your air conditioner is running nonstop, it’s time to investigate. Identifying the root cause of a broken HVAC system might be a daunting task if you’ve never dealt with one before.

Your AC unit’s fan is constantly running for one of these causes.

The Fan Is Switched To “On”

The fan will continue indefinitely if you leave it in the “on” position. Set it to auto mode, so that only the heating and cooling system is working. Your ac unit fan will automatically turn off when it senses that the room temperature has reached your preferred level.

AC Not Working | DIY Air Conditioning Repair & Troubleshooting

AC Unit Is Too Small Or Unable To Match Settings

An inadequate-sized air conditioner will not do its job properly. The fan and blower will operate constantly if the HVAC system is too small to keep up with the thermostat setting.

In addition, your HVAC system may not reach the correct temperature if your neighborhood is experiencing high temperatures. As a result, it will take longer for the system, including the fan, to reach the desired temperature.

Faulty Thermostat

If your thermostat is unable to accurately measure your home’s temperature, the fan and cooling system will be activated when they aren’t required. As a result, a new thermostat is required.

Short Circuit Or Broken Relay Switch

Relay switches can malfunction, preventing the thermostat from communicating with the fan while the AC unit isn’t operating.

If the system doesn’t recognize the on and off signals, a wiring problem or short circuit could be at blame.

What’s Happening When the AC Fan Stays On?

“Why does my air conditioner’s fan keep on running?” is a common question. Keep in mind that your AC fan may remain on for a variety of reasons. Problems that are most frequently encountered include:

  1. Instead of “auto,” the fan is set to “on.” When the fan is turned on, it will run indefinitely. As long as the air conditioner is running, it should be set to “auto” mode.
  2. Insufficient cooling capacity or inability to cope with high temperatures. If the HVAC system is too small, it won’t be able to perform at its best. In order to keep up with the thermostat setting, an HVAC system that is too small will have to run more frequently. If the temperature outside is unusually high, the entire system, including the fan, will run longer than usual until it reaches the thermostat setting. This is because the AC is unable to achieve the thermostat setting.
  3. Faulty: The thermostat It’s possible that the thermostat has to be replaced if the fan and cooling system are running when they shouldn’t.
  4. Some sort of short or faulty relay switch is to blame. However, if only the fan is functioning, it could be that the thermostat settings aren’t getting passed on to the fan because of a faulty relay switch. Alternatively, there may be a problem with your fan’s wiring or a short circuit that is preventing the fan from turning on and off.

What Should I Do If the AC Stays On?

Are you unsure which of these issues is causing the issues with your AC fan? Identify the issue by following these three steps:

  1. Use “auto” mode for your fan. It’s best to set the fan to “auto” mode if it’s already set to “on” mode.
  2. Set the fan to “auto” and then “off.” Your thermostat may need to be replaced if the fan continues to run even after you switch the switch to the “off” position. An expert HVAC repair specialist is needed to replace a thermostat.
  3. Consider a new heating and cooling system if your current one is in need of repair or replacement. Your HVAC system may be unable to keep up with your thermostat’s setting if you’ve determined that the problem isn’t connected to the fan setting or thermostat. It’s possible that routine maintenance will be all that is needed to return the system back to full capacity. If this is the case, it’s time to think about getting your HVAC system replaced by a trained and certified professional.

Troubleshooting Your AC Fan In Three Easy Steps

It’s possible for minor issues with your HVAC system to quickly turn into significant ones. Professionals can help you identify the source of the fan’s excessive use and save costly repairs and an uncomfortable household.

In order to assist the technician in locating a potential issue, homeowners should conduct their own research prior to the arrival of the HVAC professional.

A broken air conditioner fan can be fixed by following these four steps.

  1. Check to ensure that your fan is set to the “on” option before changing the setting. Switch to “auto” to avoid the fan running when your air conditioner is on.
  2. If the fan doesn’t turn off, it could be a sign that your thermostat needs to be replaced. Your thermostat can be replaced by a qualified HVAC repair expert.
  3. It’s time to schedule HVAC maintenance if you’ve gone through the preceding steps and found no problems with your fan or thermostat. Maintaining the system on a regular basis may be sufficient to restore it to peak performance.

The following problems can be identified and remedied by an HVAC specialist:

  • Dirty Air Filtering
  • Airway Obstruction
  • Refrigerant levels are low.
  • Unwanted Power Outages
  • Functionality of the Thermostat

Repairing your HVAC system isn’t always worth the money. If that’s the case, it’s time to replace it. If your HVAC system isn’t up to snuff, a licensed service technician can help you decide whether or not a replacement is in order.

After following the methods outlined above, your HVAC professional will be able to find the main cause of the problem.

How to fix your AC: fan not spinning - YouTube

Troubleshooting Your Air Conditioner Fan Issues

  • A/C Unit Not Big Enough
  • Coil Freezing in a Refrigerator
  • An issue with the temperature sensor.
  • Relay Switch Error
  • Thermostat Problem
  • A Circuit Breaker Is Required
  • Is Your Heating and Ventilation System nearing the end of its useful life?

Let R & T Services Solve Your HVAC Fan Issues

Don’t try to fix your air conditioner on your own; it’s not worth it. For more than three decades, the inhabitants of Billings, Montana, have relied on R & T Services, a seasoned HVAC contractor.

We at R & T Services are proud of our professional HVAC technicians, and we do our part to keep them up to date on the latest repair techniques and HVAC technology. All of our installations, repairs, and maintenance calls are completed to the highest standard..

You can get a free estimate and professional HVAC services by calling us today.

Your Local Aire Serv Can Ensure Your AC Fan Runs Like It Should

Contact your local Aire Serv® to get the problem solved if you’ve done the previous troubleshooting methods and still can’t get it working.

Aire Serv’s technicians have the skills and equipment to get your AC fan back up and running quickly and efficiently, whether you need routine AC maintenance or HVAC repair. Get in touch with the Aire Serv HVAC experts at (855) 679-0011 or book a service online today.

What if the sound you hear is coming from your toilet instead of your air conditioner? Check out these advice from Mr. Rooter® Plumbing on how to fix common plumbing issues. This plumbing company is part of the Neighborly® network of trusted home service experts.


Your AC unit may have a problem with the thermostat if you can’t find a solution after the first two stages.

However, the best way to restore the system to peak performance is through routine maintenance.

Having an air conditioner in our homes has a tremendous impact on our comfort, happiness, and even our overall health. Because of this, we must ensure that they are in good working order.

Knowing what could go wrong and how to fix it are also important skills that can be demonstrated in the classroom.

Those that are well-versed in the subject matter are always ahead of the pack. So that’s all there is to “why does my air conditioner’s fan keep running?” I sincerely hope that you’ve gleaned something from this piece of writing. Click here for more fascinating articles.