Honeywell Thermostat Not Working After Battery Change [Quick Fix]

Did your Honeywell thermostat stop working after replacing the batteries? You’re not alone! In this post, I’ll walk you through some handy tips to fix this problem yourself. Let’s get started.

In short, if your Honeywell thermostat stops working after changing the batteries, remove the batteries and put them back in properly. If that doesn’t help, locate your HVAC system circuit breaker and turn it off and on. This should resolve the problem.

For more details on how to fix this problem, keep reading.

Table of Contents

How to Fix a Honeywell Thermostat that Stops Working After Battery Change

To get your Honeywell thermostat to work again after changing the batteries, here is how to go about it:

1. Check that You’re Using the Required Batteries

Honeywell thermostats use regular AA/AAA alkaline batteries (non-rechargeable batteries). So you want to ensure you’re using the right batteries—as wrong batteries may not turn the thermostat on or cause undesirable operation.

More so, all AA/AAA alkaline batteries out there are not of the same quality. So, while you get the required batteries, ensure they are of good quality, as substandard/inactive batteries may cause the same problem. So check that the batteries are active and be sure to get high quality batteries such as Duracell, Energizer, and the like.

2. Replace All the Batteries

Did you, by chance, mix old batteries with new ones? If yes, then the odds are your thermostat won’t turn on or would stop working after some time.

Using old and new batteries together may cause battery leakage, reduce overall performance, or even worse. If your thermostat batteries are low, ensure you change them all for the best performance.

3. Check that the Batteries Are Correctly Placed

Sounds like what you already double-checked? Well, a reminder in case you didn’t check after replacing the batteries.

If your batteries are not correctly positioned—the positive (+) ends pointing up, your thermostat won’t turn on. Double-check and ensure you put the batteries in properly.

4. Reboot Your Thermostat Via the Circuit Breaker

If your Honeywell thermostat won’t turn on after replacing the batteries, another fix to try is rebooting the device via your circuit breaker.

Follow the steps below to reboot/reset your Honeywell thermostat via the circuit breaker:

Go to your circuit breaker panel—it is the main power distribution panel in your home.
Locate the thermostat circuit breaker—it is usually labeled “A/C,” “Air Conditioner,” or “HVAC.”
Flip the circuit breaker off. Then wait for a few seconds and flip it back to the ON position.

Check your thermostat to see if the display is back on. If not, continue to the next step.

5. Clean the Battery Terminals

Your thermostat may not turn on if the old batteries have corroded the battery terminals—preventing current to pass through them.

Issues like this may happen if you delayed replacing the old batteries, or they had poor seals and leaked acid as a result.

If your Honeywell thermostat still refuses to turn on after trying the fixes above, chances are the battery terminals are corroded. So, check the battery terminals in your thermostat and clean them to fix the problem.

To clean your Honeywell thermostat’s battery terminals, dip a Q-Tip into vinegar or lemon juice, then rub it gently on the battery terminals surface—to remove any corrosion.

If this doesn’t help, continue to the next troubleshooting step.

6. Factory Reset the Thermostat

Your thermostat turns on but not functioning correctly after getting the above steps right? Then factory resetting could be your best bet.

That is, if you’re sure you have the right batteries and they are correctly placed, but your thermostat is not functioning correctly, then try to reset it.

Factory resetting your Honeywell Thermostat to its default factory settings will erase all previous programming/settings, thus fixing any bug.

So here’s how to factory reset a Honeywell Thermostat:

How to Factory Reset Honeywell T5+, T5, and T6

Step 1: Press and hold the Menu and then press Symbol until Reset appears on the screen.
Step 2: Now select Reset to complete the process.

And that’s all about resetting Honeywell Wi-Fi Thermostat—T5+, T5, and T6 models.

Resetting Honeywell Smart/Lyric Round Thermostat

Step 1: Press the Cloud Icon and hold it.
Step 2: Press the Down Arrow button until Reset appears on the screen.
Step 3: Select Reset to complete factory reset.

Now your device has been successfully reset to factory default settings. You can reconfigure and see if it now works correctly.

Caveat: As mentioned, performing a factory reset will completely erase all configurations, including integrations with other smart home devices. So be sure to reprogram your thermostat and connect all previously connected devices—for continuous optimal operation.

If you’re not sure how to reconfigure your thermostat after programming, contact an HVAC expert for help.

Did your thermostat turn on or now work correctly after all? If yes, congratulations! But if not, you may have to contact Honeywell for further assistance.

Honeywell Thermostat Won’t Turn on AC? Try This:

If your thermostat isn’t turning on AC, chances are there are issues with either the airflow, compressor, thermostat wiring, or the furnace. To fix this issue, here’s what you need to do:

Check the airflow to see if there’s air or not. If there’s air; is it warm or hot or at room temperature?
Check that the compressor is running smoothly.
Ensure the wirings to see if they are all intact.
Check the furnace and ensure the breaker to the furnace is turned on.

If you noticed any issue with the airflow, compressor, wiring, or furnace, click here for a step-by-step guide to fix the problem. And if you’re not sure how to check any of the above, call an HVAC technician to assist you.

Honeywell Thermostat Won’t Turn on Heat? How to Fix

For the most part, problems with a Honeywell thermostat heating system may require an HVAC professional to fix.

But it could be a minor issue sometimes and you could fix it by doing the following:

Go to your vents and check the airflow.
Examine the furnace system.
Check the thermostat wiring.
Check the thermostat screen.

Now go here for a detailed guide to fix problems with any of the thermostat sections mentioned above.

If you think it’s not something you can do, you want to get an HVAC professional to help you resolve the problem or contact Honeywell for assistance.

You may also read our article on how to fix a Brinks digital deadbolt that stops working after replacing batteries and how to troubleshoot common problems with Luxpro Thermostats.

Wrapping Up

How do I get my Honeywell Thermostat to work again after battery change?

As mentioned, if your Honeywell Thermostat stops working after changing the batteries, you can easily fix the problem by ensuring you’re using the right/active batteries and then reset factory default settings to fix any glitch.