Trailer wiring harness.

[WicAndThing]

Last weekend while towing in the rain, I had to manually turn lights on the TV on. I've never had to do that. The dealership checked out the TV yesterday and said the towing harness is OK on the vehicle.

Last night, I was inspecting the wiring harness on the camper. I had noticed in the past that there was a lot of electrical tape on the wires, but never paid it much attention until now because it worked. What I discovered bothered me... The wiring has rectangular female plug that plugs into a port on the trailer tongue. The previous owners had cut that wire and spliced in a spade plug, leaving a couple of wires unspliced. Here are my questions:
1) Is the "plug into the frame" setup typical/common?
2) What used to be on the other end of that plug?
3) My truck has the large round 7-pin plug, and a 7-pin/spade adapter. Will I be able to find the right "harness" for this setup?

Thanks,
Chad

[WicAndThing]

Last weekend while towing in the rain, I had to manually turn lights on the TV on. I've never had to do that. The dealership checked out the TV yesterday and said the towing harness is OK on the vehicle.

Last night, I was inspecting the wiring harness on the camper. I had noticed in the past that there was a lot of electrical tape on the wires, but never paid it much attention until now because it worked. What I discovered bothered me... The wiring has rectangular female plug that plugs into a port on the trailer tongue. The previous owners had cut that wire and spliced in a spade plug, leaving a couple of wires unspliced. Here are my questions:
1) Is the "plug into the frame" setup typical/common?
2) What used to be on the other end of that plug?
3) My truck has the large round 7-pin plug, and a 7-pin/spade adapter. Will I be able to find the right "harness" for this setup?

Thanks,
Chad

[Kablewizard]

I can give some light on 2 of your questions, but have no idea what used to be there.(#2)
One thought on this would be like in our case, when I added the new TV the cable was to short since the TV plug is about 6" farther away then on the old truck.

#1 The color code should be standard, since the connectors come with a color code chart.

#3 Check with your local RV supply store. I have seen 6 ft sections with connector and cable. When I did mine I found a 4 wire section of wire and since the other 3 wires had different gage wire, I just bought the wire.
I staggered the splices so the were separate. and At Radio Shack I bought shrink tube after wrapping the wire in electric tape, the shrink tube was added and shrunk. less chance for water getting in.