Why is My Honeywell Thermostat Blinking Cool on? – Fix Guide

Seeing the “cool on” message on your thermostat when you do not expect it will prompt you to ask, ‘’why is my Honeywell thermostat blinking cool on?”

Below we will explain how to go past this issue and have your thermostat working well again.

If your Honeywell thermostat blinks cool on, it could be that the system is on setup mode maybe after a power outage. Kindly change the mode to cool mode and the fan mode to ‘Auto.’ You can also lower the temperature to the lowest figure and check if the vents will produce cold air.

If not, a reset will solve the issue. Let us learn the process in detail so that you can fix the issue without much difficulty.

Why is My Honeywell Thermostat Blinking Cool On?

If your Honeywell thermostat ‘cool on’ blinks, it could be due to any of the following causes:

• The thermostat is pumping air into the system
• It is on setup mode
• The AC coils or the air filter are clogged
• The circuit breaker is tripped
• The batteries are dead

Note: There is no problem when your Honeywell thermostat blinks cool on. It only shows that the system is working to bring down the temperature.

You may only be worried if it blinks for more than five minutes. Hence, you will need to troubleshoot the issue.

How to Fix Honeywell Thermostat Cool On Blinking Issue

If you have been asking, ‘’why is cool on blinking on my Honeywell thermostat,’’ you now can smile again since you can go past the issue.

We have listed below several ways you can use to troubleshoot it. Kindly check what applies to your system.

Solution #1: Lower the Thermostat Temperature

If your thermostat displays cool on, you will need to examine if the system is indeed cooling or not, and it can control the temperature.

To confirm the same, do the following:

1. Set your thermostat to the lowest temperature setting.
2. Check the control panel to see if the thermostat is in ‘cool mode,’
3. Ensure fan setting is in ‘Auto.’
4. Give the thermostat an hour to cool, then check if the vents have cold air. 

If the thermostat still blinks ‘cool on’’ and you feel no cold air coming out of the vents, proceed to the other troubleshooting methods.

Solution #2: Check the Thermostat Mode

Your Honeywell thermostat can at times change its setting and be on the wrong setting you do not wish it to be.

The settings can be altered, especially during a power outage and your system will change to Setup mode.

It can make your thermostat blink ‘Cool on’ several times when it is on this mode.

If you notice it is on Setup mode, you will need to change the system into the necessary mode.

Also, check the time your thermostat is showing; kindly adjust it to the correct one if it is wrong.

Once you make the necessary adjustments, the issue on your thermostat should disappear within minutes.

Solution #3: Check if you Need to Change the Batteries

Your thermostat cannot run effectively if it does not have healthy batteries. If the batteries are almost dying, the system could also blink ‘cool on.’

If the thermostat has no power, the heating and the cooling system will not work.

You may note that your thermostat battery is not functioning correctly when you check the battery indicator, and it shows a low battery or is blank.

This message comes when your battery’s lifetime has two months remaining.

If you also feel that the battery has stayed for so long, you can change and see if there will be a difference.

Solution #4: Check if the AC Unit Has Power

You have already troubleshot the necessary, and it is now time to check the main system.

You need to ensure that the whole system has power. Check the outdoor and indoor units to ensure that they both have power.

If not, there may be a problem with the connections, power supplies, and sockets. This could make the thermostat blink “cool on”.

You need to ensure that all these things are correctly connected and they are receiving power.

The other thing you should not overlook is the circuit breaker. It flips off during a power outage or when the system is overloaded.

So long as it is off, your system will not work properly. If it is off, kindly trip it back on.

Note: Check the fuse too. There will be no power in the system if it is blown, and most settings will misbehave.

Solution #5: Check if the Air Filter is Clogged

The air filter filters the air that enters your system. If clogged, various issues may occur to your system, such as the ‘cool on’ issue.

It can also shorten the durability of your device and increase your electricity bills since it will cause the thermostat to take longer to heat or cool.

If you have pests or allergies, you may need to change the air filter often. However, the recommended time to change the air filter is at least after three months.

Solution #6: Check the AC Coils

Honeywell thermostat can also blink ‘cool on’ when its air conditioner coils are dirty and clogged.

Most people do not give lots of attention to the AC coils as they do to the air filter.

Hence, some bugs on the coils may be ignored and cause a significant impact on the unit.

The coils attract lots of dirt and dust over time that clog it, restricting airflow. It is always good to check your coils, inspect them for any dirt, dust build-up, and clean them.

As you do this, remember to clean the fins in the system if it has dirt or debris.

Once you are through, kindly check if the thermostat will still blink ‘cool on.’

Solution #7: Reset the Thermostat

Trying all the above tricks we have mentioned should solve the problem in your system.

However, if the thermostat still blinks ‘cool on,’ you may need to try something different, a reset.

Resetting the system should solve this and any other issue in your thermostat.

Note: You should note that the process removes all settings and programming from the system. So, you will need to set up the system again.

If you want to retain your usual settings, you can write them somewhere to use them later once the resetting is complete.

Reset it using these steps:

1. Locate the faceplate or the battery lid of your thermostat.
2. Push the faceplate inside using your fingers on both of its sides to remove it.
3. Remove the batteries and return the batteries but in their reverse polarity.
4. Wait for five seconds, then return the batteries in the correct polarity and return the battery lid.
5. Power on your system, then check if the error is still there.

Solution #8: Contact Support

A Honeywell thermostat blinks ‘cool on’ when the AC coils or air filters are dirty, or the system has no power.

Kindly clean the air filter and the AC coils, and ensure that the batteries are charged, and the system has a good flow of power all through.

You can also reset the thermostat, and the issue will disappear.

At times you may try all these methods but still, your efforts fail to pay. However, contacting the system makers should and will bear much fruit.

Get the Honeywell phone number or email from the website, contact them and explain the issue with your thermostat.

They will help you since they know the system better than you do. If need be, they can send you an expert to handle the case if your device has a valid warranty.

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Bottom line

Going through the above piece should answer your query about ‘’why is my Honeywell thermostat blinking cool on?’’

The troubleshooting measures are straightforward, and you do not need to spend too much to have your system working well again.

Just follow the tips, and you will be good to go.