Bought the parts a while back to hook up :neutral::neutral:brakes to camper plug on back of my 99 Suburban. Where do you wire the box under the dashboard, how do you tie into the back?? I'm an fng with this sort of stuff but a sorta maintenance-savvy(butsomewhat electronically-challenged) buddy is helping me. We first thought it would plug right into the code box. Yeah, the code box. Any help appreciated.