If the thermostat is still unresponsive, make sure the breaker is shut off and remove the cover. If it looks dirty inside, use canned air or a soft artist brush to clean away accumulated grime that may be affecting its functionality. Then look for issues like loose wiring or terminal screws and tighten them up.

What would cause a thermostat to stop working?

Look for and address simple reasons why the thermostat isn't getting power, such as dead batteries or a tripped breaker or blown fuse in your main electrical service panel. If you're certain it's receiving power, shut off the thermostat breaker in order to safely take off the cover and examine the inner components.

How do you know if your thermostat is not working?

The most common signs of a broken thermostat are: The thermostat display is off or is non-responsive when you try to adjust it. The display on the digital screen is faded or incomplete. The furnace or air conditioner does not respond when you adjust your thermostat.