Originally Posted by Craig.Evans
I thought my Suburban furnace was acting up because of erratic 12V supply but the power's all fixed up and I've still got this symptom:
The furnace will start and run till the thermostat shuts it down. The van cools, but the furnace won't start a new cycle of heat. i can hear a faint electrical hum at the furnace when the thermostat asks for heat, but it won't start. Come back another day and the same thing happens.
Has anyone had this experience?
It sounds like the air circulating motor may have a dead spot or tight bearings when warm. If you pull the furnace out and try to run it without gas, the fans should still run so you could watch and even give the motor a spin to see if it would start, if that was the issue.