I did the physical install of the tail lights a long time ago. The wiring was all routed to a central location so I could tie into the existing trailer lights. But I lost the notes. And the wires have been dangling from the trailer so long the sharpie had faded. Now I have five wires and no idea what they do.
I spent what seemed like hours with my multimeter ensuring I know what wire did what. And…that it did nothing else unexpected. This last but was due to the fact I have an extra wire hanging labeled “Red” that seems to go nowhere and does nothing.
After some research on wiring colors and plug pin-outs I had my diagrams and was ready to splice. But there is not enough slack in any of the factory wires to splice neatly. Then here comes the luck…
Near the trailer tongue is a covered box with terminal connectors for each of the six used wires on the 7-pin plug. (It seems reverse was not important enough to wire or provide lights. Considering this was a ‘car’ hauler and the towing vehicle would be visible it makes sense.). Thanks Mirage for keeping things neat and serviceable. I wish other trailers in my life were so organized. (If you are looking, they make quality 10,000# rated trailers right here in Nampa, Idaho USA.)
I measured out four (Brake, running, Drivers Ground, Passenger Ground) lengths of wire and purchased a junction block. this will allow me to avoid wire nuts, tape and loose connections later.
I hope to get the wires connected in the morning while it is still cool. (You know the 60’s.) Today we broke 100 so any time outside needs to be before my work is in the sun.
As a side note: It seems the 500ft spools of wire I purchased were an investment. I have used nearly half of the white and a 1/3rd of the black. I have also used a lot of colored tape to identify wire. Why buy numerous colors when ID’n both ends works.