How To Fix a Honeywell Thermostat Blank Screen? (11 Ways)

Last updated on April 12th, 2024

Last week I walked up to increase the temperature on my Honeywell thermostat only to discover a blank screen. I got totally confused because I hadn’t seen anything like this before.

I went to the internet for help, and that’s where I discovered that a Honeywell thermostat blank screen is more common than one would appreciate. But that also meant I got a lot of troubleshooting tips to remove the blank screen.

I’m going to share all of those with you so you can fix your Honeywell thermostat blank screen.

Before we dive into how to fix it, let’s understand why this happens in the first place.

Reasons for Honeywell thermostat blank screen

A blank screen on a Honeywell thermostat is daunting because then you cannot possibly know the actual temperature or set a new temperature. I discovered that this could happen for a number of reasons. And it is your job to pinpoint what exactly is causing the blank screen. So let me share all the possible reasons for a Honeywell thermostat blank screen.

  1. Your Honeywell thermostat batteries have run out of power, and you need to replace them.
  2. One of your electrical breakers has tripped and caused power issues.
  3. The safety switch on your HVAC system has been enabled. Your HVAC system has a safety switch on the compressor that automatically switches on if the refrigerant pressure goes too high or too low. The safety switch should only be tested by a technician who has the proper tools to do so.
  4. The wiring of your thermostat might be set wrong. This happens mostly in the case of newly installed thermostats. Maybe the wiring is loose or has lost its connection, and that’s causing a disruption to the power of the thermostat.
  5. Your furnace is off, or the furnace door is open, which has turned off the furnace. Since the Honeywell thermostat gets most of its power from a low-voltage transformer on your furnace.
  6. Your thermostat panel is not mounted properly.
  7. The power surge protection fuse on your thermostat is blown.
  8. The high-temperature limit switch on your HVAC system is tripped.
  9. The float switch on your HVAC system is tripped.
  10. There is no 24 Volts voltage between R & C terminals on your thermostat, which means your thermostat has failed.

In my case, it was the dead batteries that caused the issue.

Fixing Honeywell thermostat blank screen

All the above issues can be fixed with simple troubleshooting methods except for the last one. The last reason means that you have to replace your thermostat with a new one. Before you get overwhelmed by thinking that you might have to replace your thermostat, let’s look at the possible solutions that I discovered.

1. Replace Honeywell thermostat batteries

Replacing the thermostat batteries
Replacing the thermostat batteries

The most common reason for a blank screen on a Honeywell thermostat is dead batteries. If you have a busy schedule like me, it is completely possible to miss the low battery notification on your thermostat screen.

When the battery dies out, the screen goes blank. I forgot to replace my batteries, and that’s what made my screen blank. When I replaced them, the thermostat was working again, just like before.

Honeywell thermostats use AA or AAA based on which model you have. You can check the old batteries to buy exactly the same ones. Once you get the new batteries, replace them with the old ones.

Depending on which Honeywell thermostat model you have, the procedure to replace the battery also varies. You can check out the separate procedures for various thermostat models in our detailed guide. But the gist of it is as follows:

Step 1: Turn off the power switch on the thermostat.

Step 2: Open the battery compartment.

Step 3: Replace old batteries with new ones.

Step 4: Close the battery compartment.

Step 5: Turn on the power switch on the thermostat.

If you see a Honeywell thermostat blank screen with new batteries, then one of the below solutions could work for you.

2. Check the electrical breaker

Check the circuit breakers
Check the circuit breakers

Your Honeywell thermostat is wired to your house’s electrical system. Sometimes, when the power goes off, and there’s no backup power for your thermostat, the system breaker gets tripped. If this happens, you have to switch the breaker back to the on position from your electrical box.

If you are not familiar with the electrical box, then we suggest you contact an HVAC professional to deal with it. But if you want to do this on your own, try to locate a breaker switch labeled either HVAC, AC furnace, or heater. Flip the switch to the on position, and your display problem should be resolved.

If the breaker is in on position, you can turn it off and back on manually to reset the electrical network on your thermostat. Now, check if the screen error has been resolved. If not, the issue could be something else.

3. Disable the safety switch on the HVAC compressor

As discussed in the reasons section, the HVAC system compressor has a safety switch. This switch is tripped when the refrigerant pressure becomes too high or too low. This could also indicate a blockage in the pipeline.

So when this switch is tripped, all the functions are halted. That could also cause the Honeywell thermostat blank screen.

This safety switch should only be inspected by a trained technician. They have the proper tools to do the task and repair the system if necessary. You shouldn’t interfere with the compressor on yourself as it’s a risky task that isn’t recommended as a DIY activity. So let the professionals take care of it and repair the blank screen issue.

4. Check the thermostat wiring

Check the thermostat wiring
Check the thermostat wiring

Have you just installed your Honeywell thermostats, and the screen is not turning on? You probably might have connected the wiring wrong.

New HVAC systems have 5 wires – W, G, Y, Rc, and Rh. But the older systems only had 4, where the R terminal was single. Each of these wires should be connected to the respective terminals on the thermostat. You will find labeled terminals on your thermostat.

In case the wires are not labeled with appropriate alphabets, here’s a little guide to identify which wire is which.

Wire labelUsed for
WFor heating
GFor fan
YFor cooling
RhFor heating transformers, like a furnace or heat pump
RcFor cooling transformers like air conditioners
Different wires of the HVAC system connect to the Honeywell thermostat

Caution: Don’t touch the writing without turning off the power from the breaker system, or you could get an electrical shock.

Connect each of these wires to the appropriate terminals and fix them in place. If you have only one R terminal on the thermostat but both Rc and Rh wires, then insert both the wires in the R terminal together. Once you have fitted all the wires, cross-check if they are right. Finally, close the thermostat panel and power it on. On correct wiring, the blank screen should turn on.

5. Close the furnace door and turn on the furnace

Close the furnace door and turn on the furnace
Close the furnace door and turn on the furnace

When your thermostat is connected to a furnace, the status of the furnace influences the behavior of the thermostat. So if the furnace is off, the thermostat screen could also go blank. The solution is simple – turn on the furnace. The furnace switch is usually located on a wall beside it. Simply flip it on.

Some of the furnaces have advanced safety options. They automatically get switched off when the furnace door is opened. If you have accidentally left the furnace door open, the furnace will not turn on no matter what switch you flip. So, first, close the furnace door and then flip the furnace switch. This should bring the Honeywell thermostat blank screen back to life.

6. Check if the thermostat is mounted properly

Check if the thermostat is mounted properly
Check if the thermostat is mounted properly

Sometimes, when you mount the front panel, you don’t press it hard enough to fit perfectly into the frame. This could loosen the electrical contact between the batteries and the device. As a result, the screen doesn’t get the necessary power to turn on.

To resolve this, all you have to do is press the thermostat front panel firmly into its base and ensure it is placed properly. This should resolve the electrical contact issue and give power to the Honeywell thermostat blank screen.

7. Check for a blown fuse on the thermostat

Check the blown fuse
Check the blown fuse

The Honeywell thermostat has a fuse near the control board. Just like a regular fuse, this could blow because of a sudden surge in electricity. The blown fuse will shut off the entire thermostat system, including the screen. This causes the blank screen issue. You can change the fuse and get the screen working again.

Step 1: Switch the thermostat off and open the front panel.

Step 2: Locate the fuse near the control board on the thermostat.

Step 3: Check the fuse parameters and buy a replacement fuse matching those.

Step 4: Take out the blown fuse and replace it with a new one.

Caution: If you don’t know how to replace a blown fuse, call an experienced person for help.

Step 5: Put the thermostat back in its position and turn on the power switch.

The entire system should start running again, and your screen should no longer be blank.

8. Check the high-temperature limit switch

Whenever the temperature of your HVAC system rises above a certain limit, the high-temperature limit switch is tripped. This also automatically turns off the thermostat screen so you don’t change the temperature, which will create more pressure on the system.

This is kind of a safety lock. The switch turns back off when the temperature of the system is decreased. You just have to wait it out. You cannot and should not manually turn off the temperature switch because that will damage the HVAC if its temperature continues to rise. Just wait for the screen to turn on.

If a long time passes and your screen is not turned on, you should consider alternative solutions.

9. Check the float switch

Your HVAC system has a float switch. When the switch is open, it automatically turns off the thermostat screen. This switch is open in two cases:

  1. The drain is clogged
  2. Moisture is detected inside the furnace or AC.

If the drain is clogged, you need to clear it up so the float safety switch will be turned off. Check the drain, and if you see a blockage, try to clear it. You can blow air with high pressure or use a small vacuum cleaner to suction the debris. This should clear off the clogged drain of your AC and switch the float switch.

But if the issue is the moisture inside your system, there’s not much you can do about it. You need to call a trained technician to remove the moisture content from your furnace or AC.

Once these issues are resolved, the Honeywell thermostat blank screen should turn back on automatically.

10. Check voltage between R and C terminals

As discussed earlier, the Honeywell thermostat has different terminals where you connect the wires from your HVAC system. It is an unwritten rule that the voltage difference between the R and C terminals should be 24 Volts. So, you need to confirm that this voltage difference is present between the said terminals.

Step 1: Open the front casing of the thermostat.

Step 2: Insert a multimeter between R and C terminals.

Step 3: Take the voltage reading between the two terminals.

Ideally, it should be 24 Volts. But if it is less than 24 Volts, that means the air handler isn’t powering up the thermostat. Thus, your Honeywell thermostat has failed and will need to be replaced.

11. Replace the entire Honeywell thermostat

In case of low voltage between two terminals or you or a technician not being able to identify what’s wrong with the thermostat, you need to replace the entire Honeywell thermostat unit with a new one.

This will cost you a bit, but it’s better than not being able to control the heating and cooling in your house. If your product is still under warranty, you might get partial or complete replacement support.

Conclusion

A Honeywell thermostat blank screen is a really bad issue because you won’t be able to change the temperature or any other settings. Unless, of course, you have a Wi-Fi thermostat that you can control with a mobile app. Irrespective of that, you have to fix the blank screen to avoid any further issues with the HVAC system.

You now know what causes the screen issue and how to tackle each of these issues. You can try these troubleshooting methods one by one to fix the screen. If nothing works, contact the customer support for more help.

FAQs

Do I need to reset my Honeywell thermostat to fix the blank screen?

No, you don’t have to reset your Honeywell thermostat to fix the blank screen. You can try one of the above-mentioned methods.

Why is my Honeywell thermostat not turning on?

Your Honeywell thermostat could not be turned on because of power issues like low battery or tripped breakers.

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Siddhi Gurav

She is the editor and content writer at Smart Home Bulls. Siddhi merges her passion for language with SEO expertise. With 4 years of experience as a creative writer and a passion for smart home technology, she fits in perfectly at Smart Home Bulls. Her wide experience in content marketing has been an excellent addition to our team.

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