Trace the wires, Trace the wires!

[Bigcountry]

First thanks to all that repeated the mantra "trace the wires".We have a new to us FR Flagstaff pop up and the first trip out I had no DC accessories. I remembered seeing a green wire hanging down from behind one of the support posts. Found where it went and got it back in thinking its a ground. Checked the fuse and it had blown a 20a but the reverse polarity on the battery fuse was fine. Changed the fuse and it immediately blew again but reverse polarity is fine. So I troll through the posts and then climb underneath. White is going to positive on the battery and then trace it to at least three ground points on the frame. Uh oh there's my problem. Also found that my inline battery disconnect dead ends underneath the trailer. Looks like it was abandoned at some point with a new wire run. Charged up the battery and voila DC accessories.
Will have to work on the in line disconnect.

Great discussion, great help. Thanks