Thermostat keeps resetting, restarting, or randomly changing. 10 Causes and fixes explained

Written by Adam Morris
4 Min read

Thermostat keeps resetting, restarting, or randomly changing – causes and fixes

If your thermostat keeps resetting itself, restarting, or randomly changing, you may be wondering what the problem could be. There can be a few possible causes for this issue, and luckily, there are also some simple fixes that might help. Knowing what could be wrong and how to fix it will help you get your thermostat running smoothly again in no time.

 Programmable default settings

If you have a programmable thermostat, one issue may be that it’s resetting to its default settings when the programmed schedule kicks in. If you have it set to a certain temperature, but it keeps resetting to a different temperature each time, then you should simply adjust the default settings. Most modern programmable thermostats allow you to customize settings for different periods of the day, so you should be able to find the right settings for your comfort level.

Weak batteries on non-programmable models

Non-programmable models usually rely on batteries to keep the temperature setting, and if the batteries are weak, they can cause issues such as randomly changing and resetting. If you notice that your thermostat is always resetting to a different temperature, try replacing the batteries with new ones. This should resolve the issue and keep it at the same temperature.

Man adjusting thermostat

Blown fuse

Another possible cause for a resetting or randomly changing thermostat is a blown fuse. If it isn’t working properly, check to see if the fuse has blown. If it has, then you’ll need to replace it with a new one. For safety reasons, make sure to turn off the power before replacing the fuse.

Wiring issues

Finally, if all else fails, your problem may be related to loose wiring or an electrical issue with the thermostat itself. For example, if the wires are loose, then the signal won’t get through properly, causing it to reset or randomly change. To fix this issue, you may need to call a licensed electrician to inspect the wiring.

Replacing your thermostat

If all of the above troubleshooting measures fail, then it may be time to replace your old thermostat with a new one. Choose one that is compatible with your system, including your air conditioner, furnace, and/or heat pump, and follow the manufacturer’s instructions for properly installing it. Once it’s installed, you should be able to get it up and running without any more problems.

Expert Tip

If you’re unsure of what is wrong with your thermostat, it’s best to consult a certified electrician or HVAC technician to inspect your system. They will be able to diagnose the issue and recommend the best solution.

Check the display

Before doing anything else, it’s a good idea to check the display to see if it’s still working properly. If the display is blank or flickering, then something is wrong. In some cases, you may be able to fix this issue by simply resetting it, but if that doesn’t work, then a replacement may be needed.

Check the air filter

A dirty air filter can cause the air handler on your heating and air conditioning system to overheat, which can cause problems with the thermostat. To prevent this from happening, make sure to check your air filter monthly and replace it as needed. This can help keep your system running smoothly and without any unexplained temperature fluctuations.


The location of your thermostat can also affect its performance. If it’s too close to a heat source or in direct sunlight, then this could cause issues. For the best results, make sure to mount it away from any sources of heat or direct sunlight.

Dirty heat exchanger

If you have an older furnace, then it may have a dirty heat exchanger, which can cause problems. In some cases, the heat exchanger can become so clogged with dirt and debris that it causes a short in the wiring. If this is the case, then it’s best to call a professional to clean the heat exchanger and replace any worn-out parts.

Dampers aren’t working properly

If you have a forced-air system, then your thermostat may be having issues because the dampers aren’t working properly. Dampers control the flow of air throughout the system, so if they aren’t working correctly, then this can cause issues. Make sure to check the dampers and replace them if necessary.


In some cases, the problem may not be with the thermostat itself, but with the sensors. If the sensors aren’t working correctly, then this can cause it to keep resetting or randomly changing. To check the sensors, you can use a multimeter to make sure they are working properly.

Check for interference

If you have a wireless thermostat, then there may be interference from other electronic devices. This can cause your thermostat to keep resetting or randomly changing. To fix this issue, try turning off any other electronic devices that may be causing interference.

Faulty wiring

If the wiring in your home is faulty, then this can cause the thermostat to act up. Faulty wiring can cause a whole host of issues, so be sure to have it checked out by an electrician if you think this might be the cause of your problem.


A bad capacitor can cause your thermostat to act up as well. The capacitor helps to keep the current flowing, so if it’s failing, then this could cause it to reset or randomly change. To test the capacitor, you can use a multimeter to see if it’s functioning properly.

Replace the unit

If none of these fixes help, then it may be time to replace your thermostat. Choose one that is compatible with your heating and cooling system, and follow the manufacturer’s instructions to install it properly. Once the new one is installed, you should be able to get back to enjoying consistent climate control.

In conclusion, if your thermostat keeps resetting or randomly changing, there could be several causes, such as weak batteries, a blown fuse, wiring issues, or a programmable model resetting to its default settings. To fix the problem, try replacing the batteries, checking the fuse, tightening any loose wiring connections, adjusting the settings, and/or replacing it altogether.

Appliances made simple. 

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