This is a fairly new Goodman forced air furnace. I replaced it in 2014 or end of 2013. All our bedrooms are upstairs where it gets pretty warm even when it's cold outside without heater. We hardly need any heat at night so I reduced it yesterday to 60. However, when I woke up, the temperature on the first floor was 53 so I checked the thermostat and it's at 60 but heater is not running. I tried turning off/on several times, increased temperature, reset thermostat etc... but nothing. I turned the fan to On instead of Auto and I hear fan is running but no fire in the furnace. What to check? Is thermostat bad? Is there a way to test it by jumping the wires behind? I read filter and fuse can also cause this issue. If fuse is out, fan wouldn't turn on right? Is the igniter bad? I want to check few things I can before calling professional help as they are pretty pricey, specially when it's cold outside. thanks for suggestions.