How To Wire a Gooseneck Trailer from Scratch with Just Trailer Lights

Question:

Thanks for info!!! Now if i want to add a extra 12volt light for sight like outside living quarters door what would i tap into so it will be hot while truck is not running and i could add on off switch? Does this need to be fused?

asked by: Steven

Expert Reply:

You should not need any extra fuses. Trucks like the Dodge Ram 2500 are built for towing and should have enough power on those circuits. First I would wire the lights to the trailer and worry about the 6-Way last.

I would wire the lights with the standard color code. That way if you sell the trailer or have to work on the wiring in the future, it is done in the standard method. The white wire is ground and should be attached securely to the trailer frame. It is best to have direct contact with the trailer frame, so clear any paint away as it can act as an insulator. Brown is for running lights/tail lights, so run it down both sides of the trailer and connect it to the clearance lights and the tail lights. Run the green wire down the right side for right brake and turn signal, and run the yellow down the left side for left brake and turn. If the lights have ground wires, again, make sure they have direct metal contact.

Once you have the lights mounted and wired, move up to the bed of the truck with the 6-Way. Bring a circuit tester, like part # 40376, a black marker and masking tape or a label maker. Plug the 6-Way with the wire leads into the 6-Way of your truck. Have someone in the cab operate the brakes, turn signals and headlights so you can identify which wire is which. Use the circuit tester and find which wires are right blinker, left blinker, running light and ground.

I have added a link to a wiring FAQ page that shows what pins serve what functions if a 6-Way is wired according to standard.

If you want to simplify things, since you are not using brakes, just lights, you can attach a 4-Way flat connector, like part # 18044, to the trailer wiring. You would then use a 6-Way to 4-Way adapter like part # 37325. This way you should not have to search wires.

expert reply by: Patrick B

Steven

2/16/2010

Patrick B.

2/16/2010

You could go ahead and use the 12 V accessory wire. It should have been fused when the 6-Way was installed. It draws power directly from the vehicle battery. I would install an LED light if available as it will not draw as much current as incandescent lights. Do not run the light too long or it will drain the truck battery. Every few hours, start the truck and let it run for 10-15 minutes to re-charge the battery.