What does upfiititting in fuse box mean
Not sure what you asking? Why are you in the fuse box on your new truck?
Don't have power to 7 prong trailer connection so trailer battery is recharged when hooked to truck
I'd consult the dealer service department on this issue or the trailer hookup manufacturer. Try some online Sierra forums, maybe some owners ran into the same issues.
Maybe just a fuse. You do have a warranty so I would suggest that you use it.
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