Where is the Running/Brake Lights Ground on 2015 RPod 178?

[alanlearned]

I am replacing a corroded and troublesome OEM brake/tail lights/turn signal light cable. My kid brother is familiar with the issue and over the phone he mentioned something interesting. He said 9 out of 10 times running lights etc. problems are related to corroded 12v dc ground connection. Now my question is this: Where is the ground to the frame on a 2015 178 R-Pod or is there some other sort of grounding for running lights/brake lights through the 110v ac?

[chriscowles]

Running lights on my Mini-Lite have dual conductors. They are not grounded to the frame. If you find the same to be true on your RPod, consider whether the ground problem (if it is a ground problem) could be on the truck end of the trailer connector.

There's probably a junction box screwed to the frame under front of the trailer. It's where your trailer umbilical cord connects to the running lights and trailer 12V power. Check there to make sure all connections are good. Also, check both the plug and socket for the Bargman 7-pin connector.