Just bought a boat to pull with my 02 Ram. My truck already has a 7 plug on the bumper and a 4 pin flat plug underneath my truck. The trailer only has a 4 pin flat plug so I bought an adapter to fit my truck. The 4 pin on the trailer plugs into the adapter and I plug that into my truck. The adapter has 4 red indicator lights so you can see the connection is made. Only 1 red light is lit and I have no lights on trailer. I checked all the fuses I can except the clear square fuses (1-15 on the fuse box lid) and the big light blue fuses(73 on the lid) cause I don't know how to check those. When I use a tester on my truck connections, only one pin lights up the circuit tester. Bought the truck used and 7 pin was already on the truck. Did previous owner wire it wrong ? Any suggestions would be greatly appreciated.