1985 Uhaul 13-CT, Wiring Diagrams? Troubleshooting

[Scoutmarm]

My wife gets huge Kudos for all the work she's done on our UHaul 13-CT. New AC, flooring, cabinets, interior decorating, temporary tail lights, etc. Been her pet project for a few years now. There is however this on-going battle with getting the original running and tail/brake/turn signals rewired. Have original curved lights, buckets, etc. in the back. Yet...after miles of new wire, connectors, stuff, countless hours and colorful language....still a no go. Working off an old faded wiring diagram, but hoping there's help for her out there before we toss in the towel. I am looking for a solid, original wiring diagram plus trouble shooting tips/experience of those who may have struggled with the same thing. TIA for any info that might help get this last project over the goal line

[Kevin A]

Don’t give up! The success of working lights is usually tied to solid connections, good bulb sockets, and a clean ground. The running/marker lights and taillights are wired straight back from the tongue connector, with branches going off to each side. The toughest part is threading the wire through tight places in the fiberglass shell, so I have run new wiring in a protected casing under the trailer back from the tongue and then up into spaces near the lights. If I had to drill small holes in the floor edge, I made sure to fill them well after everything tested OK.

Where have you already run new wiring and connections? Do any of the lights work? Is your tow plug working? There are several inexpensive meters and test lights you can get from an auto parts store to test the plug for live connections.

[mary and bob]

Originally there were two wire cords coming out of the tongue, one on each side. They were made to plug into special "tap-a-light" bulbs that would replace the original car bulbs. Those wire cords were cracked with bare wire exposed on our Uhaul so I pulled it all out. To use a standard 4 wire plug, I got a long cord with a molded on 4 prong plug from etrailer. I ran the cord along the tongue and up through the floor into the storage area just to the rear of the closet. At that point I installed a junction box. From that box I ran new wire to each tail light for turn / stop / tail, and ground. Note that the original tail lights had two bulb sockets. The lower socket is for the red part of the lens, which is tail and stop lights. The top socket is also for a dual filament bulb, but only one filament is used for the turn signals (amber). The other wire is not connected. I only used the red part of the lens until installed a set of the all red lenses, which are no longer available. The wires for the marker lights drop down between the walls and are glued in spots to the outer shell so I left them and connected them into the junction box tail light wire. The trouble spots are the grounds, both at the marker lights where the ground wire is just under one of the screws. Those marker lights can be the source of water leaks. Another ground issue that took me a while to figure out was the tail light bulb socket. First get a socket brush and clean the sockets and contacts. Make sure the contacts don't get out of position. Then see that the bulbs fit tight in the sockets, this is where I had a ground issue. To tighten the bulb in the socket, at the slot in the socket, bend it in slightly at the point where the pin on the bulb turns in to lock the bulb in place. If you want to use the amber part of the lens you will need a converter for that, also from etrailer and other sources.These old trailers seem to be prone to modifications, some of them obviously done by butchers, so you never know what was original or modified. Tail light options is a whole other discussion.