I bought a new ceiling fan to replace an existing one. (the existing one worked, I just didn't like the way it looked). There's only 2 wires from the ceiling. The new ceiling fan has four wires: green, black, white, and one combo black/white. The light works as long as I connect the combo black/white. The fan only works with the green and black from the fan connected to the black in the ceiling, and then the white to the white. That's how the old fan was connected, but the old fan only had 3 wires, green, black and white, it didn't have the combo black/white. Shouldn't the green be for the ground wire? I'm confused why the green needs to be connected for the fan to work. And I'm confused as to how the wires should be connected so that the fan and the light both work. Also since it's an old house and there's only 2 wires in the ceiling is there anything that can be done regarding grounding? There is a wall switch that can be used to turn the fan/light on and off.