That doesnt sound good joe at all. I would start looking at farthest point wires burned. The fact it burnt all the way to fuse box is confusing. Fuses shoild of popped, my thought is ehat kind of pain +$ to fix wirings of the hummer. Not a good start to the year! !. You hauled the old rig with the hummer right. What difference between old trailer wiring and the new one?