The picture shows my front wires associated with the 7-way plug. The brake wires are the black and white two on the left side inside the red sleeve. The break away pair are on the left side. One is red, one is gray. Both 12 gauge I think. In the picture, they're tied together with a wire nut. Please ignore the wire nut. It's not right. The red wire is the power wire that the tongue power jack also gets it's power from.
The wires going right are the coach lights and one of them is red. That's the red Andy is referring to. As seen, my trailer has two reds to the 7-way, both associated with different things. My picture is how I found things. I have since fixed it all and reinstalled a fuse panel.
I wired my trailer according to this wiring diagram. The trailer running lights on my trailer matched the colors shown in the diagram. My brakes and my break away switch wire colors didn't match colors. My main 12 volt
power line to the battery is 10 gauge blue.
I did splice in the diagram colors to my 7-way plug so if somebody comes behind me they will be able to immediately figure out what everything's for because the colors match the diagram as well as the Airstream Service Manual.
I believe my trailer wires are as installed by the original equipment manufacturer. There was no evidence at all of any panels removed for access nor were any of the original furniture built-ins ever removed.