Have model H8MPN075B12A1 (furnace) and NAC036GKC3 (AC) units. Neither of the units are working. I have reset the breakers for both units. The fan will turn on the furnace if switch on the thermostat is tuned to on but in auto nothing works with either unit.

Thanks,
Steve

Turn power off to the furnace and pull stat to expose the wires. Remove R, W and G then twist together. Power up the furnace, if it starts up stat is bad.