You may have the charging fuse between the truck and camper charger blown. Ours did that a lot when using the jacks without shore power. Anyway, I found the fuse, of all places, under the sink right to the left of the charger electrical panel. It was high in the under sink cabinet. There was no mention of the fuse placement in any manual I could find. So much of these campers were excellent, and then you find some bonehead construction detail. It was a 30 amp in a single fuse holder, like an afterthought.