Switch question for rear defroster

I un boxed the one I have and I only see 1 feed wire to the blower motor but the switch is a 3 position. (on,off,on or off 1-2) I am in the middle of Christmas decorating right now. If I have more time in the next day or so I would like to get out the multimeter and do some testing. I don't see any mention in the instructions about that either except it does say to dress the wire from the switch. (not wires).