On the passenger side in the hood area - where the Slee 2nd battery tray goes to - there is wire loom there in a rubber boot. If you look in that rubber seal/boot there is a niple that you can cut - this will allow you to feed the wires you need to get through the firewall.
On the passenger side foot well. There is a plastic cover - it was a plastic nut you can unscrew and above that is where the wiring you have inserted will come through. You can peel the carpet on that side (removing the plastic trim on the door sill that holds the carpet down and run the wires all the way to the back of the truck)
Just another place where you can run wires through firewall.
