I have an issue may y?all can help. I bought a vintage trailer and changing the the plug from a 4 flat to the original 7 way plug. Tail lights work previously. I reran wires to new plug and only my right turn and right tail lights work. Both sides work if I put on my 4 way flashers. I thought maybe bulbs so I got wired and straight connection from my tail lights to my battery on my camper. They both worked. Does anyone know what would be causing this issue? I hope I explained it clearly.