Thanks folks! I was stuck not knowing what to do next...
I think I may just rewire my old trailer with newer LED lights. Kits are dirt cheap and I have a broken plastic lens anyway. Im not well versed in all things towing and never owned a RV and not even clear about the different ends ( plugs ) , All I know is my new RAM has a few plugs so I'll try and figure out some options this weekend.Or just grind the paint off the receiver and the hitch 😂
In all seriousness though i would add a new ground that goes to all the lights like mentioned and swap the 4 pin for a 7 pin (last part is optional but i just hate 4 and 5 pin connectors lol)