How to fix Honeywell Thermostat Cool on but Not Working? (2022)

How To Reset Honeywell Thermostat

A thermostat is an essential part of any HVAC system. Our homes and workplaces are more comfortable because of these devices, making it simple to adjust the temperature. A Honeywell thermostat is one of the most common thermostats on the market.

Even though these technologies do an excellent job of keeping us comfortable, issues occasionally arise. We’ll go through some of the most frequent Honeywell thermostat issues and provide some advice on fixing them.

When I originally received my Honeywell thermostat, the ‘Cool On’ signal that flashed on display attracted my attention. With no prior experience with Honeywell thermostats, I couldn’t figure out what this message was attempting to tell me.

It brought back memories of my Honeywell Thermostat’s connectivity troubles. I was able to decipher this warning after studying online and consulting the user handbook.

The ‘Cool On’ sign on your Honeywell Thermostat lets you know when the thermostat has started working in your HVAC system, much like the other operating modes.

In the case of a power surge, the compressor is protected by a safety mechanism integrated into the system. A Honeywell thermostat may be reset if the light flashes for more than 5 minutes and no cooling have occurred.

This article discusses how to fix difficulties with ‘Cool On’ on your Honeywell thermostat and the many factors that may have led to this problem.

Steps To Fix Issues: Honeywell Thermostat Cool on Not Working

Your Honeywell thermostat’s ‘Cool On’ indication should stop blinking after five minutes.

You can take measures if that doesn’t happen, and they can be found below. First, if you have a Honeywell analog thermostat, you may check the settings to ensure they are set up appropriately. You’ll note that your thermostat has a switch for heating, cooling, and turning the fan on and off. To find a solution, switch on the heat setting and raise the temperature.

You’re in luck if it powers on. If your thermostat doesn’t turn on at all, something may be wrong on the inside. You may want to check the thermostat’s inside to determine a problem. To begin, go to your electrical breaker box and shut off the thermostat power. The next step is to turn off the thermostat and gently remove the unit’s top.

The wiring should be checked for loose, damaged, or separate components. Everything should also be checked to determine whether it’s in working order. Your thermostat may be malfunctioning because it is dirty or has loose wiring. If there are no problems behind the cover, your HVAC system may malfunction, or you may need a new thermostat.

Finally, it’s time to put your air conditioning to the test. The thermostat should be set to the cool setting, and the fan should be set to Auto. Wait a few seconds before lowering the temperature again. You’re fine to go if you can hear the system operating! If this is not the case, there may be another problem at hand.

One of the most prevalent issues is a blank display screen when switched on the system. Some Honeywell thermostat troubleshooting hints may be of use, though. To determine whether or not you have a dead battery, check the screen of your digital thermostat. If nothing else, try swapping out the batteries.

If that isn’t the case, the HVAC system may blame. If your HVAC unit’s access door isn’t entirely shut, your screen may seem blank. For the unit to function, these doors must be closed. The system won’t operate if a door is open since this switch isn’t activated. Make a point of thoroughly inspecting your abode and ensuring that all entry doors are locked.

Another possibility is that a circuit breaker has been tripped. This may potentially result in a blank screen on your thermostat. It is important to check the HVAC unit’s circuit breaker to ensure that it is correct.

Set Thermostat To Lowest Temperature Setting

Make sure your thermostat is set to Cool and the lowest possible temperature.

Ensure that the fan setting is set to Auto, particularly if your Honeywell Thermostat indicates cool on, but no air seems to be coming out of the vents. In this way, you can see whether the cooling in your house is properly controlled by your thermostat. For a while, keep it on the lowest setting and keep an eye out for any fluctuations in temperature.

Alternatively, you may experiment with various temperature settings to determine whether your thermostat is making the appropriate decisions when it comes to turning down the temperature.

If everything goes according to plan, the problem is most likely with the HVAC system rather than the thermostat. If the thermostat is the source of the issue, you may want to try some solutions listed below.

Reset Honeywell Thermostat

Check If Thermostat Is In Setup Mode Or If The Clock Is Set

You may find your thermostat in setup mode if the power is off for a brief period. This may cause your thermostat’s “Cool On” light to flicker.

The problem will be resolved on its own if you finish the setup in this case. Make sure the clock on your thermostat is switched on and set to the right time, as well.

Check The Thermostat Batteries

A low battery might also be a factor. The thermostat can’t initiate heating or cooling if the batteries are low. Check your thermostat’s display for a ‘Battery Low’ signal to see if this is the issue.

There is an average of two months before a Honeywell thermostat begins to show this. If your thermostat is powered by 24 volts rather than batteries, you should inspect the thermostat’s wiring.

Take a look at your C-wire for any signs of damage after shutting down your machine. Your Honeywell Thermostat’s batteries need to be replaced if it was installed without a C-wire.

Another typical issue is a blank display screen when the system is switched on. However, there are Honeywell thermostat repair instructions available for the most part.

A dead battery might be the cause of a blank screen on your thermostat’s digital panel. Check to see if it helps to replace the batteries.

If that isn’t the case, the issue may stem from your HVAC system. Leaving an access door open on your HVAC unit might cause your screen to seem blank. Doors that are closed trigger a switch that permits the device to function. This switch is disabled if a door is open; therefore, the system cannot function. Examine your storage space and make certain that all doors are locked.

A tripped circuit breaker is another possibility. A blank screen on your thermostat may also be the result of this. It’s important to double-check the circuit breaker for any HVAC devices you possess to ensure the switch is set correctly.

Check If Air Handler/Fans, Furnace, And AC Unit Have Power

A low battery might also be a factor. The thermostat can’t initiate heating or cooling if the batteries are low. Check your thermostat’s display for a ‘Battery Low’ signal to see if this is the issue.

There is an average of two months before a Honeywell thermostat begins to show this. If your thermostat is powered by 24 volts rather than batteries, you should inspect the thermostat’s wiring.

Take a look at your C-wire for any signs of damage after shutting down your machine. Your Honeywell Thermostat’s batteries need to be replaced if it was installed without a C-wire.

My tutorial on changing Honeywell Thermostat Batteries is extensive.

Check Indoor AC Filter And See If It Needs Changing

Dirt tends to build up fast in the interior air conditioner’s filter. Because it has to work harder to clear the debris, a filthy air filter increases your AC’s power consumption and the likelihood of a breakdown.

AC filters aren’t only important for the quality of the air you breathe; they influence the rest of your heating and cooling systems as well. To keep your air conditioner running at its best, it’s advised that you replace your AC filter every three months.

Check AC Coils And See If They Are Dirty

Check for clogged or unclean outdoor AC coils, just like you would with the interior AC filter. Dirt may build upon these coils over time, causing problems with ventilation. A filthy air conditioner will not perform as effectively as if the coils are unclean.

Check the coils of your air conditioner to determine whether they are clogged. Be cautious about switching off the main unit first before cleaning the coils if necessary.

Cleaning the area around the air conditioner and ensuring sufficient distance from its surroundings will also help guarantee that the airflow is not impeded.

Reset Your Thermostat

After exhausting all other options, including checking for thermostat malfunctions and equipment flaws, there is one last thing you may do.

Thermostats may be returned to their default settings by performing a factory reset. However, you will lose all of your thermostat’s settings and programs if you do so. As a result, before you attempt to reset your thermostat, prepare a list of all the settings you’ll need.

Depending on the type of your thermostat, the actions you must take to reset it are different. It’s up to you whether or not your model includes a “Menu” button; pressing or holding the button will bring up the choices “Reset,” “Factory,” and “Factory Reset” if it does.

‘Menu’ may be found under ‘Preferences’ in certain models. If you’re unsure how to do it, you may look up specific instructions for your thermostat model online. Do not reset your Honeywell thermostat until you have turned off the electricity to it, just in case.

Restoring your original settings and operating your Honeywell thermostat normally is possible after successfully resetting the device.

Call Honeywell Support

If none of the above alternatives worked, the last option is to contact Honeywell’s Customer Support. Help them identify your problem and resolve it faster by explaining all the procedures you did to troubleshoot the problem to them.

Final Thoughts

Keep the furnace door closed and the furnace’s power switch turned on when “Cool On” is engaged. Make certain that the furnace’s circuit breaker switches are also turned on.



Does the Honeywell thermostat have a reset button?

The ‘Menu’ option on most Honeywell thermostats is a reset button. It is possible to access numerous reset settings simply by pressing and holding the ‘Menu’ button. The fan button may also double as a reset button on certain older thermostat types.

How do you reset a Honeywell thermostat when it is locked?

You must first unlock your Honeywell thermostat before you can continue with the reset process.

Simply push the center button to release your Honeywell thermostat from lock mode. You’ll then need to type in the passcode you’ve established. 1234 is the default password.

You will be able to reset your thermostat after entering the code and pressing “Select” on your keyboard.

What does permanent hold on the Honeywell thermostat mean?

For an infinite amount of time, you may manually override the scheduled schedule on your Honeywell thermostat by using the permanent hold option.

You must push and hold the button until a message shows, depending on your model, to activate this function.


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