I originally posted this on a Ford Truck forum but I thought some of the knowledgeable folks here may know.
My friend just bought a 2016 F-350 with a few aftermarket additions: light bars, air bags, aux reverse lights. There is also a switch to the left of the steering wheel and we have no idea what it does. It is a rotary dial that seems to have 4 positions it will "click" into. We don't think it's related to the light bars or air bags because we've found the controls for those already. Some other info: the truck is set-up to tow a 5th wheel trailer and has some lights installed inside of the bed that we don't know how to turn on.
Any ideas what this thing does?