Installing a Fantastic vent with proper sealant

Well that got me thinking: it must be looking for a high current (or low voltage) on the motor circuit. I could install a power resistor in series with a diode, paralleled with the motor, so that UP it would stop but DOWN (current reversed) it would run and shut for the rain sense. But I would still have to pull the knob out then push it back in every time I adjust. I guess I ought to just buy one "take it out of the box" and see what I could do with it.