On the passenger side towards the right of the fire wall, if you pull back the carpet and the rubber behind thats behind it, you will see or feel a what looks like a rubber grommet/plug in the fire wall. If you take a screwdriver and push it out it will give you access through the firewall to run a wire. I got a 10ga wire through no problem so I'm sure you could go a gauge or two larger. Next you will need to look under the truck behind the plastic in the right forward wheel well. You can pull it back just enough to get your hand in there and feel for the hole. You'll know if your looking in the right spot if you see a wire harness. If your looking toward the rear of the truck the hole would be on the left of the wire harness. Took me awhile to find it but its there. Check some other threads cause one guy actually posted a picture of the holes location in the cab.