10. The controller comes with a three-position switch that gives you full control over the fan if you need it. The three positions are Off, Normal, and On. With the switch in the Normal position, the controller will be running the fan; Off will shut the fan off no matter what the controller is telling it; and On turns it on, again no matter what the controller is telling the fan. You don’t need to wire this switch into the system if you don’t want to; the controller will function just fine without it.