Thermostat Not Working? Here’s How to Fix It (easy)

This post has been Last Updated 1 month ago by Kunal

A thermostat is a crucial device that regulates the temperature in your home. When your thermostat is not working, it can lead to discomfort and inefficiency in your heating and cooling systems. In this article, we’ll explore common issues, troubleshooting steps, and solutions for malfunctioning thermostats.

Quick summary

Thermostat troubleshooting steps:

  • Check the batteries
  • Make sure the thermostat is set to the correct mode
  • Verify that the thermostat is properly calibrated
  • Check the wiring to the thermostat
  • Clean the thermostat sensor
thermostat not working multiple images combined

Preventative measures to avoid thermostat failure:

  • Regularly change the batteries (if applicable)
  • Keep the thermostat clean and free from dust and debris
  • Avoid exposing it to direct sunlight or heat sources
  • Schedule routine HVAC system inspections and maintenance

Please note that these are just general guidelines. If you are unsure about any of the steps or if the thermostat issue persists, it is always best to consult with a qualified HVAC technician.

What are the signs and symptoms of a thermostat that is not working?

When a thermostat is malfunctioning, you may notice symptoms such as

  • Inconsistent room temperatures.
  • HVAC system not turning on when needed.
  • Frequent system cycling.
  • Unresponsiveness to mode adjustments.

Why is it important to have a working thermostat?

A working thermostat ensures comfort, energy efficiency, and cost savings. It maintains your home at the desired temperature and prevents overuse of heating or cooling systems.

What are some common causes of thermostat failure?

Various factors can cause thermostat issues, including:

  • Dead batteries (if applicable).
  • Incorrect mode setting.
  • Calibration problems.
  • Loose wiring connections.
  • A dirty thermostat sensor.
  • A faulty thermostat itself.
honeywell thermostat has a blank display dead

Fixing a thermostat not working

Fix 1: Power Issues: Check the Batteries (if applicable)

If your thermostat uses batteries, replace them with fresh ones to rule out power issues.

Fix 2: Correct Mode Setting: Ensure Optimal Comfort

Are you feeling chilly or overheated? Let’s ensure that your thermostat is in the perfect mode to keep you comfortable all year round! For instance, during the colder months, make sure your thermostat is set to “heat” to keep you nice and cozy.

Fix 3: Calibration for Accuracy

Use a thermometer to compare the thermostat’s reading with the actual room temperature. Adjust the thermostat if they don’t match.

Fix 4: Wiring Connections: Stay Secure

amazon smart thermostat display wont turn on any advice

Ensure that all wiring connections between the thermostat and the HVAC system are secure and properly connected.

The wire connection should be properly aligned to work flawlessly. 

Fix 5: Sensor Maintenance: Keep It Clean

Dust and debris can affect the thermostat sensor’s accuracy. Use compressed air or a soft brush to clean it.

Fix 6: Fuse Replacement and Wire Inspection

Someone on the forum suggested that there could be a fuse in your HVAC system. They recommended checking the wires at your furnace to find the circuit board where the fuse might be located.

Another user advised inspecting the wires, especially the red wire going to the thermostat, which appears to have a small nick. They suggested using electrical tape to fix the issue.

It’s fixed! Thanks for all the suggestions, I tried connecting them directly, and still doesn’t work, but just so happens I also have an electrician around to help with other, unrelated, things … I asked him about it and he checked the breaker. Lo and behold, the breaker is bad and needs replacement.

Fix 7: Jumper Adjustment

Now it’s not necessary that the jumper adjustment work for everyone but here are my thoughts on it: 

A Telkonet Touch Thermostat on a wall, set to 72 degrees Fahrenheit.

Another user advised removing the jumper between W/E and W2 and placing it between the two red slots to address issues with the furnace fan not spinning when the AC is turned on.

Fix 8: Heat Pump Thermostat Consideration

It was mentioned that your thermostat appears to be for a heat pump system, which could explain the jumper between W/W2. This could be the reason behind the behavior you described.

And also you should consider the heat pump thermostat because it’s crucial. 

Fix 9: Fuse Blown

As per our previous conversation, I mentioned that both the previous and new thermostats were not receiving power without batteries. It was suggested that the replacement of thermostats might have caused the 3-amp fuse on the furnace control board to blow. To prevent such a scenario, I recommended turning off the furnace breaker before making any thermostat changes.

Fix 10: Discussion with OP

The discussion with a technician in the UK in an email concludes with him stating that I have to replace the blown fuse and inspect the wires.

If you’re unsure about any of the steps or if the thermostat issue persists, it’s advisable to contact a qualified HVAC technician for a thorough inspection and repair.

thermostat image with thermostat not working overlay text

Preventative Measures

To avoid future thermostat issues consider these preventative measures:

  • Regularly change the batteries (if applicable).
  • Keep the thermostat clean and free from dust and debris.
  • Avoid exposing it to direct sunlight or heat sources.
  • Schedule routine HVAC system inspections and maintenance.

Preventing thermostat failure

To avoid thermostat issues, follow these preventive measures:

  • Change the batteries regularly (if applicable) to ensure continuous operation.
  • Keep the thermostat clean by regularly removing dust and debris that can affect sensor accuracy.
  • Avoid placing the thermostat in direct sunlight or near heat sources, which can lead to incorrect temperature readings.
  • Have your HVAC system inspected and serviced regularly to identify and address potential problems.

Here is a list of some of the most popular thermostat companies in 2023:

  • Ecobee
  • Emerson
  • Honeywell
  • Nest (Google)
  • Tado
  • Carrier
  • Schneider Electric
  • Lennox
  • Mitsubishi
  • Bosch
  • Viega
  • Sensata Technologies
  • Thermcraft


That’s it for today’s blog. Today I showed you how to fix the thermostat not working, with all the relevant information and images. I personally have a thermostat, and when it’s not working I just do the jumper adjustment and calibration.

It works, for me, if you have any queries do let me know in the comments or contact us.

I'm Samuel, a technical author with expertise in mobile technology. I write how-tos and fixing tutorials for a variety of tech products, including Android phones, iPhones, and Macs. I have a deep understanding of how these devices work and the common problems that users experience.I'm passionate about sharing my knowledge with others and helping them learn more about mobile technology and how to fix common problems. My tutorials are clear, concise, and easy to follow, and I provide step-by-step instructions with screenshots and videos.I'm confident that my skills and experience make me a valuable resource for anyone who wants to learn more about mobile technology or how to fix common problems.

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