a lil help needed for trailer wiring....

I just finished wiring up my old aluminum boat trailer that I just finished restoring. I got my lights mounted up high to keep them out of the water. I'm using the 4 flat hook-up on my 2004 F-150 Super Crew. Trailer Brake lights work fine both sides. Turn parking lights or lights on truck on, both trailer lights work fine. Turn flasers on truck, both trailer lights flash too. Turn left blinker on truck, left trailer light blinks fine. BUT........ Turn right blinker on trunk, both trailer lights blink. I checked the four flat terminal on truck with light tester, everything ok. Fuses ok. The green wire coming from terminal on truck goes to green wire on right trailer light. Yellow wire coming from truck terminal goes to yellow wire on left trailer light. White wire (ground) coming from truck is grounded on trailer chasis. Now .... The brown wire coming from the truck terminal goes to the brown wire on the left trailer light. AND I ran another wire off of that same brown wire coming from the truck terminal to the black wire on the right trailer light. Maybe thats where I screwed up but I figured thats where the black wire coming from the right light went... Whats wrong???? Thanks for any help.. Fishermanms

Re: a lil help needed for trailer wiring....

I believe brown is running and tail lights.

Re: a lil help needed for trailer wiring....

By the way the black wire is really brown.... And you say "Ground".....
What do you mean?????

Re: a lil help needed for trailer wiring....

Yes the brown wire is tail lights when I turn on truck lights and the green and the yellow are for blinking...

Re: a lil help needed for trailer wiring....

Here are the color codes.

White is ground. Be sure to ground the trailer with the white wire from the pigtail. Don't rely on the ball to give you a ground.

Brown is running and tail lights.

Yellow goes to Left side only for stop and L turn lights

Green goes to Right side only for Stop and R turn light.

Hope that helps

Re: a lil help needed for trailer wiring....

Trailer Wiring Diagram

Re: a lil help needed for trailer wiring....

Thanks..... The plug on my truck has three female, green, yellow and brown and one male, white. So I bought a 4-plug to match. I spliced into the brown about halfway to the lights so the one brown T's off left and right to serve both sides. So I've got it wired just like the illustration... But I just dont get it. The only problem I have is when I turn on the right blinker ... both lights blink. BUT.... Also when I turn on my lights on the truck and try the right blinker... Nothing blinks. Not even the right blinkers on my truck...But turn the lights off on my truck... My right truck blinkers work but both lights on the trailer blink at the same time.......

Re: a lil help needed for trailer wiring....

Most likely it is a bad ground at one of the lights. Probably the right taillight. Make sure where the light bolts to the frame everything is very clean of rust, corrosion or paint. You can also make a ground jumper wire to go from a light mounting stud to the trailer frame. Make sure the jumper goes to the main part of the frame as opposed to the part of the trailer the light is hanging on. If you are not using new lights, make sure everything is clean inside the light. External tooth starwashers between the light mounting nuts (or ground jumper screw) and the trailer also help to make a good ground connection. Hope this helps.

Re: a lil help needed for trailer wiring....

AND I ran another wire off of that same brown wire coming from the truck terminal to the black wire on the right trailer light.

Click to expand...

Usually,......
If there's a Black wire coming from a Tailight,...... It's the light's Ground.......

How many,+ What Color are the wires On the right tailight housing,..??..??....

Re: a lil help needed for trailer wiring....

Bond-O could be onto something. Some trailer tail lights have three wires coming from them, 2 are black and 1 is red. One black, usually slightly larger in gauge than the other black one, is ground and the other is running.

I would back all the way up. Verify that the plug end on the truck is wired correctly first (check each pin for function), then if/when it is correct, move on to the trailer. Don't count on any colors being correct on the truck, check it with a meter...

Re: a lil help needed for trailer wiring....

I appreciate all the help... The lights are new. AND these old eyes were wrong about that wire being black. Its BROWN too. Also I did run a wire from one of the ground bolts of the light to the chasis where I drillled and installed a new ground bolt and There is star washers there as well as on the light...but I still have the problem. I also did check the wiring on the truck with a light tester to idenify if they matched the trailer and they do. I'm now wondering if I spliced off the wrong wire going to the brown by mistate. I got miles of electrical take there to insure waterproof conditions. If that fails I will have no choice but to remove the boat and more or less start completely over. But I think my problem may be somewhere in the green wire and or ground.... Thanks for all the help... Fishermanms

Re: a lil help needed for trailer wiring....

Whenever you get weird behaving trailer lights, make sure you have a good ground at all of the light fixtures and the white wire where it attaches to the trailer frame. Some wire the white wire to the ground connection on every fixture but there is no better ground than the metal frame. Next, make sure the dual filament bulbs are inserted properly. They are keyed but the sockets are so sloppy the bulbs can be forced in wrong.

Re: a lil help needed for trailer wiring....

I had a similar problem with my trailer lights.
I'd be willing to bet it's a bad ground connection somewhere. In my case, the ground wire was loose coming off the wiring harness on my truck. Make sure to check that.

Also, be sure to check the trailer ground wire that runs off from the connector. Mine was painted over,(the previous owner re-painted the trailer) so I removed it, and sanded the paint off where it connects to the frame, and I think that helped too.

Like Silvertip said, when you have weird things happening with trailer lights, its usually a ground problem.