Why Does Honeywell Thermostat Go Blank?

There is hardly anything that can stress us out more on a hot day than a blank thermostat. Thankfully, the dark display is usually an easy fix.

A Honeywell thermostat will go blank, in case the device is off (there is no power, the circuit breaker had tripped, the batteries are dead), there are issues with the wiring, or the safety switch had tripped. Low display brightness can also be the root cause of the problem.

Why Does Honeywell Thermostat Go Blank?

  • The thermostat might simply be off
  • There is no power to the thermostat 
  • The circuit breaker had tripped or there is a blown fuse
  • The batteries are dead or the thermostat is recharging
  • There are wiring issues
  • The brightness of the display is too low
  • The furnace door is open
  • The safety switch had tripped
  • The thermostat is broken

Read: Why Does Honeywell Thermostat Say Waiting For Equipment?

Why Does My Thermostat Go Blank Sometimes?

It might look like the thermostat went blank if the device is located in direct sunlight. In case the display’s brightness is set to low, the device will look like it has a black screen when the sun is shining.

Honeywell Thermostat Goes Blank Then Comes Back On

This is one of the main indicators of a short-cycling HVAC system. It looks like your unit is turning on and off way too often.

This might happen if:

The thermostat is located in the wrong place

If the device is located in direct sunlight, then it will fail to correctly read the temperature in the house. As a result, the commands that the thermostat will be sending to the HVAC system won’t be logical.

There is a refrigerant leak

A low level of refrigerant will lead to uneven pressure. This, in its turn, will make the compressor turn on and off, and the same will happen to the thermostat.

There is insufficient airflow

When the airflow is restricted (due to a dirty filter, for example), the evaporator coil might become frozen. Such an issue will make the unit turn on and off more often.

The HVAC system is too big for your house

Finally, the unit will short-cycle, if the heating or cooling system is too powerful for your house. Units that are too big end up reaching the desired temperature extremely fast.

Even though that might seem like a good thing, the truth is that short cycling will drastically increase your energy bills and will also increase the unit’s general wear and tear.

Read: Why Does Honeywell Thermostat Keep Turning Off?

Thermostat Blank but Fan Works

The fan might end up working even if the thermostat is blank, in case you have turned it on via the fan switch (it doesn’t require battery power).

Replacing the batteries and resetting the device should fix the issue.

Honeywell Thermostat No Display with New Batteries

  1. Make sure that you have installed the batteries correctly
  2. Ensure that you have chosen the right kind of batteries and that they are strong enough
  3. Reset the thermostat
  4. Check the wiring
  5. Check the circuit breaker
  6. Make sure that the furnace door is tightly closed

Read: Why Does Honeywell Thermostat Say Temporary?

Thermostat Is Blank and No Heat

If the thermostat is not working, then it won’t be able to turn the heat on. Check the batteries and the wiring – one of the wires might have been damaged or there are loose connections.

Thermostat Is Blank and AC Not Working

Thermostats that are experiencing a problem of any kind will lose connection with the air conditioner. Make sure that the thermostat has not gone bad and that the batteries are fresh (don’t worry, the chances are high that your cooling system is totally fine).

Read: Honeywell Thermostat Not Reaching Set Temperature? Here Is Why

How Do You Fix a Blank Thermostat?

The good news is that in the majority of cases, you’d be able to fix a blank thermostat in a matter of minutes.

Change the batteries

If the Honeywell thermostat does not have a C-wire, then it, most likely, needs batteries in order to operate. In case you haven’t changed the batteries for quite a few months already, then you might have to do that.

Check the circuit breaker and the fuse

If something had made the breaker trip, then simply flip it back. If you have noticed a blown fuse, then you would have to replace it.

Check the wiring

At times, the vibrations from people walking can make the wires come loose. If you feel comfortable working with electricity, then you can tighten the wires and/or replace the ones that are damaged.

Check the furnace door

Your thermostat might go blank if the furnace door is not properly closed.

Check the safety switch

If you have an air conditioner or a heat pump, the safety switch can get triggered by a clogged condensate pan. Simply empty the thing and the issue should go away.

If your thermostat is over 10 years old, then it might have worn out and you would have to replace it.

How Do I Reset a Blank Honeywell Thermostat?

Practically all battery-operated thermostats can be reset to factory settings by inserting the batteries backward for around 10 seconds and then putting them back in correctly.

To reset the Honeywell 9000 series thermostat, press the MENU button, select PREFERENCES, and choose RESTORE TO FACTORY SETTINGS DEFAULT.

Read: Honeywell Thermostat Troubleshooting Guide

Honeywell Thermostat No Power

If there is no power, your thermostat display will go blank. Simply replacing the batteries might be enough to fix the issue.

In case the thermostat is not battery-operated, you would have to check the circuit breaker and the wiring for any loose or damaged connections.

What Causes No Power to Thermostat?

  • A tripped circuit breaker
  • Old batteries
  • A tripped safety switch
  • A faulty thermostat

How Do I Get Power to My Thermostat?

If the batteries are new, the breaker had not tripped, and there are no blown fuses, then a tripped safety breaker might be to blame.

In air conditioners, water overflow in the condensate pan can trigger the switch. When it comes to furnaces, an overheating issue will make the safety device go off.

Do Honeywell Thermostats Have Batteries?

Not all Honeywell thermostats require batteries.

Those that do, usually have an LED display. In the majority of cases, they run on AA or AAA-type batteries.

How Do I Know If My Thermostat Needs a Battery?

The LED screen will start showing a ‘low-battery’ message 2 months prior to complete depletion. Bear in mind that some models will instead flash the snowflake icon. 

To find out, if your device actually has batteries or not, you should look for a battery compartment (for 5000 and 6000 series) or remove the faceplate (for 1000, 2000, 3000, 4000, and 8000 series).

What Way Do the Batteries Go in a Honeywell Thermostat?

When inserting the new batteries, note the directions of the positive and negative sides.

Can Honeywell Thermostat Run Without Batteries?

A thermostat can only run without batteries if it is connected to the power grid.

However, even the devices that have special compartments for batteries, can actually run without them, if the thermostat has a C-wire. In such a case, the batteries can become a backup power source. 

How Do I Fix an Unresponsive Honeywell Thermostat?

What should you do, if your thermostat display is no longer blank, but it has become unresponsive?

  1. Reset the thermostat
  2. Check and fix the wires
  3. You can also try disconnecting the thermostat from the circuit board and then restoring the connection.

How Do I Get My Honeywell Thermostat to Work?

  • Replace the batteries
  • Check the circuit breaker
  • Replace the HVAC system’s air filter
  • Check the wiring for any loose or damaged connections
  • Reset the thermostat

How Do I Know If My Thermostat Is Broken?

To find out, if it’s your thermostat that is faulty or another element in the system, you can try bypassing the thermostat with a jumper wire.