First, I wouldn't route cables INSIDE the frame rail - that would be a big PIA to fish the wires through there... route them on top of the frame between the body and the frame (best location IMHO). Make sure they are at least 4" away from any exhaust and that they cannot rotate around the frame (so be sure they are attached good).

Do not use the frame to ground large wires - theres a reason why this isn't done for the starter.... Run two wires one power and one ground right to the source.

Now... I would make this aux. power switched. You can do this several ways. First I would go and buy a starter solenoid for say an escort or something (external starter solenoid) and wire it up through that. Then run the switch wire either to a switch on the dash or tie it into the ignition switch so that when the key is on it will be on. This all of course would be dictated by how you plan on using it....

I don't like the idea of having large cables, that aren't always being used, running the length of the truck and always hot... bad things can happen that way....

Scott

I agree about the ground cable. Don't use the frame.

To avoid a car-b-que, I would suggest a cutoff solenoid in the circuit. Warn makes a kit, but it is easy to make your own. Get a solenoid (relay) like is used in golf carts to control power to the motor. It looks like an old Ford starter solenoid, but it is rated for continuous duty (unlike starter solenoids). Connect the relay such that the hot cable to the back is only powered when you flip a switch somewhere (usually in the cab). This will prevent the cable from being hot except when you are using the rear winch.

Dave B.
www.BlueHummer.com