2001 chevy 2500 aux light

were does the wire go from the aux switch to?
does it go to the roof or the front?
my truck has a plow prep packege on it an trailer towing package

That switch controls a relay. I'm pretty sure that it goes to the back of the cab. There should be a relay in the rear cab corner on the driver's side. If you turn the key on without starting the truck and push the button on and off you should hear the relay clicking making it real easy to locate.