Hello, I am visiting my uncle and his natural gas furnace is not working for forced air heating. There is hot water in the house, but I cannot get heat. I replaced the thermostat and cant even get the blower to operate in ON, never mind AUTO. He says it has been very temperamental lately where it won't start with the blower in auto and he has had to reset the main breaker and play with the thermostat.

Any tips for diagnosis tomorrow? I plan to try to jumpstart the blower to see if the motor is fine. Thanks guys, I have 24hrs to fix this problem for him.