OK, I looked again at my owners man and it says fuse 107 is for trailer battery charging. Aparently I miised the trailer part the first 4 or 5 times I looked. And, as you've probably guessed, its blown. Hopefully this solves the problem. I bought the truck about a month ago used, and the fuse was blown for the trailer marker lights as well, so they must have blown this one too. We camp primitive as well, with an on board Onan gen, and 2 batts as well. Hopefully this works, were off to Denali Park( Mt. McKinley ) for the weekend and a drive along the Alaska Range fishing along the way...where there is nothing... Thanks for the help...
Scott