I was able to pull my lower front interior skin over the weekend to get at the junction between my pigtail and the 12v
exterior wiring. Incredibly, no access panel was provided to get at the wiring, so I had to remove this skin panel.
Remarkably, all of the wiring and lights checked out good with no problems.
Here are the wiring colors for my external lights:
Green - Running Lights
Red - Left Turn
Brown - Right Turn
Black - Brake Lights
Blue - Electric Brakes
White - Ground
I have one question. Why the separate black wire for the electric brakes? Were all trailers in the 1950s wired this way? Today, the brake lights are part of the turn signal lights. Should I just ignore this black brake wire when wiring up my lights to my pigtail?