Update:

I worked on this yesterday and this is what i found out.
I have 12.3 volts from my truck plug.
I have 12.3 volts through the 7 pin to 5 pin adapter from Boat Mate
At the 5 pin it has 2 of each wire molded in,
2 Brown < running lights >
2 White <ground>
Several others for the tail and turns < not important >

Checked voltage out of that plug and everything was 7.5v

What i first did was unplug the License plate light as this is a 194 bulb not an LED BAM instantly my LEDS got real bright again. So i thought i found my problem. Checked my Voltage and it was now 9.5 up 2 volts from where i started.

I then started checking each light thinking i might have a shorted LED light. Each light has a small LED board inside.

Each time i disconnected a maker light my overall voltage increased .25
By the time i disconnected all my LED marker lights i gained 2.25v for a total of 11.7 V

Only thing connected was the tail lights, i disconnected them and had mt 12.3V

I reconnected each light and checking the voltage each time and it was a consistent drop so no big deal i guess.

And once i had everything done, i plugged the Etch Lighting LED bars in and they worked again. They were showing burned out but now they work.

IDK i talked to the Dealer and they are stumped as well. All i can think is this has something to do with the daisy chain effect of how the trailer is wired from the factory.

Unlike cars, nothing is home ran to the 12V source.