Have a furnace/ac unit has a switch on the front and one side of the switch is for cooling and the other side is heat. Cooling side works a/c unit comes on and blows cold air, flip it to heat (and yes I adjusted the thermostat) and all it does it hummmmm. It kicked on once and then won't work at all now. I took the switch and unplugged the a/c side and plugged the heat side to it thinking that if that side worked for the a/c I thought I would work for the heat. But it still just hummed. So my question is what else could be wrong. The pilot light is lit and stays lit so it's not the thermocouple.
Was wondering if it was a capasitor?