Thanks guys. OK, I took some closer pictures. Drivers side yellow light has a cable that is not connected. I will hopefully have time to connect this tonight.
When the truck is connected to the trailer; both turn signals work and both sides work when the brake is applied. When my headlights are on, NEITHER rear light works. I should be able to figure out where the one cable will connect to the yellow side light. I'm thinking I should hook up the side light and see where that gets me. Do you think the not connected brown cable isn't needed because there is already a brown cable connected from the truck to the hitch?
I can email you a picture of the hitch part if you need to see a closer image.
Thanks!!