ya I saw that, and I offere possible solutions, but asked if it has the outside plug for putting portable solar panels on, that could be it. also youer though it might be for a second panel might be it, weather it be to the plug for portable, or a second set of wires in your roof gland (if you have the plug that would make more sence.) and like I said, short of tracing the wires with a multimeter and jumpers you will never be sure. finding wiring diagrams for rv's is next to impossable as there will be a master enginering when they design it but what goes in on the floor is not the same and if they run out of a color somtimes the color change and so on...