Tow wiring harness?

[MrBrukh]

Hi y'all,
We recently bought a 2005 Sunseeker. I am trying to set it up for towing our Chevy Tracker. Have base plate and tow bar all set up. Am in process of installing a Roadmaster Invisibrake.
My issue is with the pigtail at the back of the RV.
The ground wire (large white one) has continuity to the frame.
But I have no voltage at the brown, green, yellow wires when I turn on the lights and turn signals.
The fuses and relays up front are OK.
I am wondering if the builder cut this harness when they built the motorhome to wire the tail lights.
Any thoughts?
Thanks, Pete

[MrBrukh]

Forest River warranty guy called me back today. I had just about given up on them. Good to hear back. Anyhow he said they would never cut the harness on the chassis. He said they put in their own harness for the coach.
There is a storm coming here in Houston area. Later hope to pull out on concrete and crawl under to follow pigtail from rear.