I was planning to shove some relays in that box, but then the intent behind the box changed when I realized I had so little usable wire on the truck. As you can see there's no room in there now. Breaking the trailer stuff out into a second box containing some relays is a future idea, but it'll do for now. I was going to run a good size battery positive wire to the back and then have rear-mounted power distribution to allow for easily lighting the bed and maybe some reverse flood lighting under the bumper (the same feed could be used for the relay switched side for trailer lights) but that will come later.

Any trailer I own is going to have LED lighting to be less of a burden in that way, so probably a non-issue.

I haven't gotten that far in planning for the Lincoln yet. Relays are always good but if the lamps are LED it matters a lot less.