Switch question for rear defroster

The factory map light switch is just as you described - off or on. I was under the impression that the rear defogger was a 2 speed unit, so the switch would be off, on1 and on 2. I have a couple of rotary rear defogger switches I'm using in my 47 Dodge project and they are set up the same way as your defogger switch - off, on 1 and on 2