Originally Posted by porchhound
The metal underbelly is above my frame and the stringers going across but i haven't located screws yet though there must be some on the ends and sides. When I press up on the metal it feels like it may be attached to a plywood subfloor because there is no flex in it. Good idea on the cut-outs and leaving an edge to work with for replacement! Prev owner cut small hole midway back (RH side) and tied into harness, running one underneath the trailer diagonally towards the left rear for an additional pigtail (has a ball attached to rear bumper) I think. He terminated these wires into the side of the plastic waste tank with ring terminals which confused me for quite awhile. Just looking for a clean replacement of current harness as I will be also replacing taillights and markers with LED lights. Thanks again!
My Father-in-law has a 18' aljo, either you must have a channel that they run through or even your frame rails. You can always just leave the old in and run new along the edge in conduit. If you run new and have to go through the cross brace I would drill in the top 1/4 only, so you won't get a weak spot. They don't build trailers like that anymore, now a days these new ones are just thrown together. Good luck on your project.