I'm pretty sure now I've never been charging 12v through 7-way to my rv. What I believe I've found is a 30a fuse in main fuse block which appears to be for the 12v didn't have the fuse nor the fuse opening didn't have any connection for it. I have a 2023 Laramie, 3.0 eco-diesel, towing package etc. Hope this makes sense.
thank you