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Trailer Lights - Need Help

I've got a 1999 F-150 bought new with the factory installed four connector trailer wiring harness below the rear bumper. Hooking up my son's boat trailer to it I've got no lights at all (tail, stop, turn, etc.). Hooking the trailer to his truck, Yukon, all works fine so the problem's not the trailer wiring. All the F-150 lights work fine with or without the trailer harness plugged in. The connector on the trailer is the round type with standard brown, yellow, green and white wires. I bought a four connector flat pigtail and spliced into the wires on the trailer. Being electrically challenged where would be a good beginning to troubleshoot? I can meter it if need be if I can find the meter.

Thanks in advance for the assistance.

Larry

Reply to
LHS
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Assuming you have the right connector, is there anything you need to do to activate the trailer wiring. I know on my 2000, I had to add two relays to the breaker box, and maybe something else. You might check the book about that.

Clark

Reply to
Clark

Like Clark said try putting the breakers/relays in. It should have come in a package with a electric brake trailer pigtail. Also something to check would be for a good GROUND off the 7 pin connector. Mine also came with a 7 pin to

4 pin adapter that plugs into the 7 pin that can be used I can run our jetski trailer, 18 ft boat trailer, and 5 x 10 utility trailer with no problems in the 7 pin with adapter or a 4 pin. It also works fine with a 7-6 pin adapter used for the 5x10. Hook our 18ft car trailer and I get no brakes or lights on. Once in a great while it will have very dim lights. We ran a 12" ground wire directly off the ground wire on the truck and added a female bullet connector on it. On the trailer we just added a ground wire onto the trailer jack bolt and ran it along with the harness and put a male bullet connector on it . With this added ground it works just fine with all functions operating.We plug it in when using just that car trailer and I have lights, brakes, turns etc.

It sounds weird but its the same way on my Dads 2002 model with the same symptoms on that trailer only. Mine is a 2000 model. Its worth a try and only takes a short piece of wire to try..........

Reply to
FordStyle

If you have the standard 4 pin trailer connector. Check AutoZone, etc. for a connector tester. It has 3 LEDs on it one for each circuit ( left turn, right turn, and stop ) . I got one and leave it plugged in to keep the connector from rusting. It will tell you if your connector is working. I didn't even get a trailer package on mine and have the trailer connector.

If you use a meter, just check each contact for ~12 volts ( when its' energized )to a good chassis ground.

If they don't work, start checking your fuses. GH

Reply to
GH

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