Thermostat not working: troubleshooting checklist
If your thermostat is blank, unresponsive, or not controlling your HVAC, these checks cover the most common causes: power, wiring, and settings.
Thermostat issues are usually power (dead), settings (mode/fan), or HVAC safety shutoff.
1) Is the display blank?
- Replace batteries (if it has them)
- Check breaker/furnace switch
2) Check HVAC mode and fan
- Cool/Heat set correctly
- Fan set to Auto for testing
3) Check the furnace/air handler door
Some units have a safety switch that cuts power if the panel isn’t seated.
4) Smart thermostat basics
- Wi‑Fi down can make it look “broken” even if HVAC still runs
- Reboot the thermostat
When to call a pro
If you see loose/burnt wiring or the breaker repeatedly trips, stop and call HVAC/electric.
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