Have herd of people running manual switches. If I were to wire mine up it would be a 3 way, 1) constant on. 2) runs of the factory thermostat. 3) off, I guess some people like to turn of their fan when they are in deep mud. That way the fan doesn't bog down and burn up. I havn't ran mine enuf yet to see if I need to do this yet. My chief concern would be That I would turn the switch off and not relize it tell it was to late.