mine is set up alittle different then what everyone else is running. I have a 3 position toggle switch that lets me turn the fan off when entering deep water, turn it on when I feel the bike is getting warm or put it back in the factory setting and let the temp sensor turn it on. Mine has yet to come on by the temp sensor with the relocated cooling system on the front rack.
If your plowing I would think the factory setup would be enough. But if you feel the bike is running warmer than you want it to. The manual switch would help you out.
when mudding and the radiator gets plugged, you need all the help you can get to keep the oil cool and the bike from overheating until you can find somewhere to clean it out.