i want to wire up a reverse light which comes on with a switch on my dash. similarly, i would like to do the same with a cab light. i don't want to use the stock units for either. how do i go about doing this? where do i run the wires to from the lights? - the fuse box? if so, where on the box do i run it to and how do i decide what size fuse to run? if not, how do i get power to the lights? how do i interrupt the circuit with the switch? How do i decide on a wire guage? really have no idea how to do this. thanks for the help!