I am replacing our existing furnace blower motor. The old motor had two speeds; the new one only has one speed. The old motor had 3 wires: black, white, and blue/white spiral. The new motor has two wires, both black but one has a raised ridge that I was told was the neutral or "white" wire. What is the correct way to hook up the wires?

Do you have AC on this furnace. If you do it probably needed the two speed motor... give me an answer and I will try to help.

No AC, and it's never actually run on more than the one speed even though it is capable of two.