you can buy plastic safe contact cleaner at most electrical
suppliers, that would eliminate having to replace wiring.
However i don't think this is your problem
In the fuse box under the hood there are individual fuses for the signal and running lights
, and for the charge wire. in my experience with chevy trucks, these fuses tend to be blown due to bad wiring on previous trailers (no offence intended if you've had the truck from new) I have even seen these fuses not in place. google the fuse block layout, and you should be able to find a drawing pinpointing the fuses