I've always run the cable through a hole in the firewall, then zip tied it to the inside (close to the top) of the frame rail in a few places and run it to the back bumper or in between the cab and bed to the toolbox, depending on where you want to mount it. I haven't looked underneath the Titan yet to see if there's anywhere better to run it or if this would even work, but it's worked just fine on all my other trucks and it never got ripped off or anything even on my mud trucks.