What is wrong next to my warmth? I have gas heat. The weird entry is that if I switch...

I have gas heat. The weird entry is that if I switch to "on" the fan comes on next I switch to "auto" and the heat comes out fine. It won;t work if I try to basically turn it to "auto". Today, the on wasn't working, so I had to turn it to cool, next to heat, and use "auto". So the fry comes out, seems close to it may be the thermostat. Is that possible? I don;t want to pay $100 deductible for the home warranty if I can win a thermostat and do it myself.
Getting the put a bet on bad a...
Answers:    it sound similar to the thermostat. They are not that hard to translation out, usually white/white red/red and black/black. Find a friend that has a unfinished knowledge of elect. Follow the instructions that come near it. I think White make and outstanding thermostat. Good luck
Installing rough contained by spigot?
I think you get it. It could be something else, but, a repairman will be making an educated guess, merely like you are. Thermostats are returnable (make sure).