I realize I built this for my Class C (so I can tow my boat and still have ample cargo space). However, I got some of the ideas from the truck camper folks and I also believe this to be good inspiration for that same community. So I am posting here.
It is wired so in the front the taillights are off but the amber side markers are on. When I turn the brights on, the ARB driving lights come on. In the rear all the lights work like trailer lights and the ARBs are triggered to come on in reverse only.
06' Jayco Escapade 25 E-450, 01' Rinker 272 Cuddy, 93' Wrangler (at least the body), '05 V8 4Runner (hates pulling the boat), '05 Mini S (Italian Job style). One dog "Lucy", One Perfect Fiance', & 2 jobs that limit our interaction with all of the above..
That's a nice job. I have the same box on a front hitch on my F250 - great place to store leveling ramps, hoses, tire chains in the winter, bbq too. Would be even nicer to have two boxes -