@MLA I used the trailer as a ground, and the wire ground, both read the same at each point. The meter readings where consistent any place i checked.

@parrothd I have been working on the LEDs i want to install. All the testing i wrote up today was how my trailer came optioned. I Should have measured the trailer before i touched it but i didn't. The last post is only the factory trailer wiring. Nothing has been changed or added as of this point. Trailer is a paralleled system + to + and - to -. LEDs only work in 1 direction, if you try to hook any of them up with + to - they just don't work.

@rca its the factory harness which i believe is 16 or 18