I have 2008 Silverado that came with a towing package, but not the integrated brake controller. My dealer installed an after market brake controller and I have started towing and noticed that the truck doesn't charge the RV battery as I drive. I checked the "+" pin on the truck towing connector and there is no voltage on that pin ... I called the dealer and they said that some of the time that pin is not wired but that it is in the harness and just needs to be "hooked up" at the fuse box under the hood. Does anyone know where the wire is located? And do you need to install a fuse that is not currenlty in the box?

Just for information, the dealer told me that if the truck came with the Integrated Brake Controller then the wire is always "wired".