Get yourself an accessory outlet and put in the rear cubby that the tire iron and jack handle are in. That entire rear trim removes easily and there's a big out-of-the-way flat spot inside the cubby for drilling your mounting hole. Wire it hot (don't forget a fuse, maybe 20A) with good, heavy wiring and a solid ground. Then you've got an extra outlet in the back for all sorts of stuff and a slick install to boot!