My new to me (96 Ram 2500) has a 7 pin trailer hookup, I had hoped it was a factory setup so a controller could be adapter/plug and play, but it looks aftermarket. I think the PO had a controller in the truck and took it with him. Can anyone ID this harness plug? Is it a brake controller plug, or unused factory harness? The pigtail hangs right in front of the transfer case shifter, and has a white plastic piece taped to it to make it rigid.