Furnace Not Working? Troubleshoot These 10 Things â
2019-6-15â€‚Â·â€‚If the switch is on, but your furnace is still not working, check to see if you have a tripped breaker. Your breaker box is (hopefully) labeled â€śFurnaceâ€ť or â€śHVACâ€ť next to the correct breaker. If not, look for a tripped breaker and reset it, if you can. If your furnace now has power, congratulations.