Suggestions requested - trailer lighting

[RacerBill]

I have an open trailer for the race car, old utility trailer with aluminum ramps. Rewired new rear lamps last year, and with a four pole connector, everything worked just fine.

This year, I added the wheel well clearance lights (trailer was born before they were required) and the three light bar on the back end. Hooked all the wires I put in last year to a terminal box. And now when I apply voltage to any connector in the box, I get nothing.

Here is my plan. Since I have plenty of new wire, I would start from the terminal box and run the wires from the hitch to the rear - one pair for each side, brown/yellow and brown/green. At each pint where I need to splice in a lamp (such as the yellow side marker light, combination yellow/red clearance marker, red three lamp bar...) I would cut the insulation on the long brown wire, splice without cutting the long wire, and insulate - testing for continuity and power at each splice before insulating. With this plan, I will be testing at each change before going on to the next.

Anyone see anything wrong with this plan, or can add any helpful hints?

Thanks.

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Bill Stevens
Mbr 103106
BnS Racing
83 ITA Shelby Dodge Charger

[MMiskoe]

Just get a new harness from either a parts store or someone like Northern Equipment. The cost is much less than the aggravation of dealing w/ most trailer wiring.

Also look at your grounds. I can attribute 99% of my light problems to crappy grounds. Seems that if the paint is no good, they get rusty. If the paint is good, it provides insulation.

Bear in mind it will work fine in the yard when you check it, but something will be out when you go to inspection, or after dark.

[RacerBill]

Problem solved with the trailer wiring. Thanks for the words of advice. After couple of hours tracing the wiring in the van to the harness on the hitch (wiring in the van did not match the Haynes manual - typical exterior wiring page)and verifying that I had current at the hitch, I plugged in the trailer and got mixed results. Now I have a terminal box on the trailer where I join the trailer-to-hitch harness to the trailer wiring. There are three connections, other than the ground, one to the running lights and one each to the left and right turn lights. The documentation that came with the harness said that the brown wire was the running lights, red was left turn and green - right turn. I disconnected the trailer side, verified the harness side with power from the van, and connected the trailer side back so that they worked.

Side markers are all tied in. Now just have to secure the wires as I just kind of laid them out on the frame.

Thanks, again.

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Bill Stevens
Mbr 103106
BnS Racing
83 ITA Shelby Dodge Charger

[ITANorm]

Wire colors for trailer wiring are supposed to be standardized (blue for brakes, etc.), as are the hookups on the standard 7-pin "RV" plugs. Sadly not everyone who wires a vehicle - or repairs a trailer's wiring, sticks to the codes. I had to figure out the wiring on a trailer once where a previous owner had rewired it. Everything on it was 14 ga. red wire.

[RacerBill]

What I found was that the car-side harness that I installed on the van pluged into the back of a recepticle. The trailer-side harness pluged into the front of the recepticle. The recepticle has a spring-loaded cover that also serves as a locking device to lock in the trailer-side harness plug. Molded onto the cover is a diagram of the plug (7 connector). The connectors in the plug matched the diagram.

The trailer was wired correctly - the right lights came on when I applied voltage directly to the terminals in the terminal box.

What was wired incorrectly was the harness itself. What came from the van came thru the car-side harmess ok, thru the recepticle ok, and went into the trailer-side harness ok. But what came out of the trailer-side harness was not correct and I had to trace the voltage and apply the wire with voltage to the correct trailer terminal.

All those years of troubleshooting computers helped! Made me think in a logical manner.

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Bill Stevens
Mbr 103106
BnS Racing
83 ITA Shelby Dodge Charger