With some assistance of two guys on the Amerigo owners page on Facebook, and a wiring color code posted there, I was finally able to get it all figured out. The wiring was direct to the truck plug, and the ground wire to all the marker lights was trashed. I pulled new ground wire to each light, and grounded to the aluminum trim all around the top of the camper, and now have fully functioning lights again.
I didn't run new wire to the tail lights at this time, as I was racing rain storms the entire time, and didn't want to have the skin panels off if a big storm rolled through. I'm also planning on doing a full rebuild this summer during the dry season, at which point I'll be replacing all the wire in the camper...especially the extension cord a prior owner ran to the AC unit, lol.
