I have a 30 something or more year old furnace that won't turn on, I think I blew out the switch that changes its speed and when you turn the thermostat on it fires up the grill but the fan never turns on. I want to see if the blower even works, it has three wires coming from it. White black and red. Can I put a cord on this and plug it in? If so which wires do I use?

I tried black on negative and red on the switched positive side and got nothing, then removed the red and changed it for white and blew the circuit. Should I dare try red on positive and white on the negative?

Yes I have no idea of what I'm doing, and its COLD! :)

Black is high speed hot, red low speed hot, and white common/neutral. Be careful.

Black is high speed hot, red low speed hot, and white common/neutral. Be careful.


Be very careful