Honeywell Thermostat Cool On Blinking But Not Working? – Complete Fix Guide

Your Honeywell thermostat cool on blinking but not working may be caused due to problematic batteries.

There’s a notification bar on your thermostat that will let you know the cooling is activated upon blinking. If there’s an issue, however, the cooling won’t work.

To fix the Honeywell thermostat, cool on and blinking but not working, decrease the temperature as low as possible. Examine and replace the air filter along with the AC coils. Next, ensure that your AC is getting a power supply and determine if the thermostat needs a new battery.

Before we move on with the troubleshooting, let’s learn what does it mean when your thermostat’s cool is on but isn’t working.

Honeywell Thermostat Blinking Cool On But Not Working Meaning?

On the Honeywell thermostat, there’s an icon that stands for the thermostat’s mode. If your device is set on the cooling mode, the AC in your house should start letting cold in.

Here’s how to check if the cooling is on and how to additionally enable it.

How To Check If The Cooling Is On?

With the variety of Honeywell thermostat types, there are different signs and notifications indicating what air is entering your house.

If you’re certain that you’ve enabled the cooling on your thermostat, you should be able to see a snowflake icon on the thermostat’s display.

How Do I Enable The Cooling?

There’s a chance that you didn’t enable the cooling in the first place.

In that regard, before we proceed with the troubleshooting, you should first re-enable the cooling to determine if that would solve the issue.

Here’s how to enable the cooling on your Honeywell unit:

1. Go to the “System” tab through your thermostat’s display.
2. Hit the “Cool” mode button.
3. Press the “Confirm” button beneath the mode.

Note: You should wait for the last 5 minutes after activating the cooling mode. 

It takes a while for the AC/ACs to become active and that activation period would be 5-10 minutes

How To Fix Honeywell Thermostat Cool On Blinking But Not Working?

When identifying the issue, you should include your AC as well.

If the thermostat says that the cooling is on, there is a solid chance that the issue is with the manual cooling, thus, your AC.

Our solutions will include actions against both instances and help you identify and solve the problem.

Here’s how to fix the Honeywell thermostat where the cool is on but blinking issues:

Solution #1 Change To Lowest Temperature

If the cooling doesn’t work for your system, you should crank the temperature down all the way to the lowest.

This will help you determine if your cooling system can cool at all and let you know where the issue is coming from.

Here’s how to decrease the temperature as low as possible on the Honeywell thermostat:

1. Go to the “System” tab and press the “Cool” mode button.
2. From there, tap on “Adjustments” and scroll down.
3. Locate the coldest possible temperature and select it.
4. Tap on “Confirm” and wait for around 5 minutes.

Pro Tip: While you’re at it, ensure that the fan settings are set to “Auto”, so you can avoid overheating of your configuration.

The RPM of the fans will reconfigure when set to auto, according to how much resource it takes for the system to produce the coldest temperatures.

Solution #2 Restore AC’s Power

If the cool icon is blinking on the Honeywell thermostat but no change in the temperature has been noticed, there’s a great chance that your AC’s power has been cut off.

This can often happen when the adapter of the AC is damaged, so during this step, you will be restoring your AC’s electricity.

Here are easy ways to troubleshoot the power of your AC/s:

• Ensure that the AC has its power adapter plugged into the power source.
• Plug your AC into a different power outlet if possible.
• Avoid plugging your AC into a power strip or divider.
• Attempt to replace the power adapter of your AC in case it has visual damage or its component adapter has been impacted.

Note: While troubleshooting, ensure that you’ve enabled the cooling on the Honeywell thermostat so you could measure the temperature change if the issue has been solved.

Solution #3 Clean/Replace Air Filter

If the Honeywell thermostat cool on blinking but is not working, there’s a high chance that an issue with your system’s air filter occurred.

If that happens, the cold wind will be blocked from entering your household and increase the total energy bill.

To replace a faulty or clogged air filter, follow the instructions below:

1. Go over to your system compartment.
2. Locate the ventilation tube along with the air filter attached to the front.
3. Undo the 4 screws on the corners of the tube and take it out.
4. Clean the air filter completely, removing all signs of dirt and dust on the fins.
5. Put the air filter back onto the tube and screw it tightly.

Note: Test after cleaning the air filter. If that doesn’t help with the cooling either, you should replace the entire component to solve the problem.

Solution #4 Replace Honeywell Batteries

Before you continue any further, you should replace the batteries of the Honeywell thermostat.

The device may be saying that the cooling mode is activated, but there might be an insufficient charge for your cooling system to work.

Here’s how to replace the Honeywell thermostat’s batteries easily:

1. On the Honeywell thermostat, remove the battery compartment.
2. Eject the old batteries.
3. Get yourself a fresh set of two AAs and embed them into the housing.
4. Re-attach the battery compartment cover that you took away.

Tip: When replacing the batteries, ensure that you’re inserting them into the correct position in the housing, so they make good contact with the electricity poles.

Solution #5 Reset The Honeywell Thermostat

If nothing helped you so far, you should perform a factory reset on your Honeywell device.

Like all other devices having an operating system, bugs and glitches can occur at any time and a factory reset is your best shot against the problem.

Alert: A factory reset is going to erase ALL software configurations, including schedules and modes of temperature. 

Make sure to inspect the settings you would need to restart later.

Here’s how to reset the Honeywell thermostat:

1. Power OFF your thermostat.
2. Open the battery compartment and eject the batteries.
3. Put them in the wrong way, thus, positive to negative and negative to positive.
4. Wait for 10 seconds and eject them.
5. Embed them in the correct way.
6. Your thermostat is reset!

Attempt the cooling mode once again. If you still struggle to get your system to cool, perhaps you should call HVAC technicians to check the problem and provide possible solutions.

Read Next: Why is My Honeywell Thermostat Blinking Cool on?

Thus, to solve the issue with Honeywell thermostat where the cool is ON but not working, replace the batteries of the device and clean the air filter. Check your AC’s power supply and change the temperature to the lowest possible. Lastly, perform a factory reset on the Honeywell thermostat to check if that will help.

Bottom Line:

Now that you know why the Honeywell thermostat cool on blinking but not working and supposedly how to fix the issue, we leave the rest to you.

In case the issue trunks out more complex than you’ve initially thought, you would need to seek professional assistance.