1995 Ford Explorer with no right turn signal or brake on popup camper

[jackcorzine]

Hae a 1995 Ford Explorer that is not passing power to the right turn signal and brake light on my popup camper. I have checked the trailer with another vehicle and all light systems work the that vehicle. I have checked continuity with the 4 pin connector pigtail from the left rear light connector to the trailer plug and it checks fine. The issue is where the right turn signal and brake signal is supposed to be passed to that connector I have no voltage (I'm specifically talking about the alternate wiring that connects to a four pin pigtail to run the power for the trailer). All other wired on this particular run of wiring are passing ~12 VDC just as they are supposed to. So I have isolated the issue to that single wire, now for the hard part. Tracking the wiring harness back through the wall of the taillight it all attaches to what appears to be a junction (maybe a brain) box with about 30 wires coming out of it. Does anyone know what wire I'm looking for to clip and splice a new wire onto it to feed teh 12 VDC to my plug? Or, do I need to run a new wire from where to the new plug to make the turn signal and brake work properly?

I looked at just splicing into the right side taillight wiring but the turn signal and brake are two distinct circuits on the Explorers taillight assembly whereas the circuit being passed to the trailer plug is only one (because there is only one bulb doing the signal on the trailer instead of two separate bulbs on the Explorer). Or is there a wire on the 6 pin pigtail hookup on the right side that I can tap into and if so which wire is it? Please advise.

Thanks in advance,
Jack Corzine