Wiring New 4-Way Connector on Trailer with 5 Wires

Question

Question:

what do color wires go to. i have on boat trailer green,white,yellow, brown with green, and brown with yellow. trying to hook to 4 flat connector

asked by: Tim

0

Expert Reply:

Going by the colors that you mentioned, it sounds like you have the typical set-up, green wire for right turn and brake, white wire for ground, yellow wire for left turn and brake, brown with green wire for right side running lights, and brown with yellow for left side running lights.

If you are using a standard 4-flat connector like part # 18004, you will more than likely be able to connect color for color for the green, white, and yellow wires. As for the brown with green and the brown with yellow, these will both need to be connected to the brown wire on the new connector.

Please keep in mind that trailer wiring colors can vary so wiring by function really is the best way.

expert reply by: Leah S

0

David R.

1/12/2021

I have a Mazda Miata with the standard 4 pin connector and i Have a small cargo trailer that has 7 wires (2 red, 2 brown, 1 green,1 white and 1 yellow) that I don't understand. What kind of connector or harness do i need to buy from you. Any help is appreciated

Reply

Jon G.

1/18/2021

Does your cargo trailer only have bare wires and no connector? I would guess that your red wires are brakes, brown are running/tail, green is right turn, white is ground, and yellow is left turn. Typically stop and turn signals are combined on a trailer so if you want to go that route let me know. You will either need to find a wiring diagram for your trailer or test your wring with 12V power to verify the functions of your trailer wiring. There are common wire colors for functions but it's always best to double check by testing. Let me know what you find and we can go from there.

Reply

Richaed L.

7/29/2024

thanks for the reply. that is what i assumed but i just needed confirmation

Reply

Jeffrey B.

4/20/2025

Have LED lights that has red yellow white green and gray how do I hook that up to a trailer with a 4 pin

Reply

Jameson C.

5/5/2025

@JeffreyB Each light has that many wires? I would assume the white is ground and then use a jumper wire from a 12 volt battery to test the rest of the wires to see what activates and then wire to 4-way accordingly. Traditional 4-way wiring is white ground, brown running light, green right turn stop, and yellow left turn stop.

Reply

Mike B.

7/8/2025

Will the hot wire on a 7 way adequatly charge a 12v battery?

Reply

Jerred H.

7/8/2025

@MikeB A vehicle 7-way connector won't charge a dead battery, but it will keep the battery topped off when you are towing the trailer. We call this a maintenance charge. You're going to need to install a battery charger like the Redarc In-Vehicle BCDC Battery Charger item # 331-BCDC1225D in order to actually charge your trailer battery.

Reply

Bobby

8/27/2025

Good morning I have a highway cargo by Carson trailer and it has five wires green/brown and yellow/brown and a white wire . I’m trying to hook up a four pin connector that has four wires, green, white, yellow, and brown. Could you please help me what is the correct way to wire it up

Reply

Nick S.

8/28/2025

@Bobby Hey Bobby, going from a 5 wire system to a 4 wire you simply will just splice the brown wires together as they are the same function, and then color match the rest as they are.

Reply

Jd

9/15/2025

Tried that Leah. Still have no turn signal on the right. Bulb has been replaced. I have tail lights, brake lights, and left turn signal only.

Reply

Robin H.

9/16/2025

@Jd check your vehicle and make sure it is sending power on the right turn circuit, then check your trailer wiring for power and work your way back. Could be a short, bad ground, vehicle or trailer side. If it is on the trailer side and you aren't able to find the short it is best to just run new wire.

Reply

Show All(6) Replies

Hide Replies

Answer 1

Your 4-pin/5-wire wiring harness is what is called a "wishbone" type which simply means that there are two separate running light wires, one brown and one pink. This allows a separate running light wire for each side of the trailer which…

view full answer...

Answer 2

Did you have a 4-pin connector that had 5 wires or was it a 5-pin connector? There is a big difference since you normally see a 5-pin connector on a boat trailer with the 5th pin used for an electric reverse lockout solenoid on a brake actuating…

view full answer...

Answer 3

Some 5-Pole flat connectors use a total of 6 wires. They operate as follows: Blue - trailer brakes Green - right hand brake and turn signals Yellow - left hand brake and turn signals Brown/Green - right hand running lights Brown/Yellow - left hand…

view full answer...

Answer 4

You will still be able to use the trailer with the 4-Way after installing the 4 to 5-Way adapter, #20036. First, you could just remove the adapter if you wanted to and then plug in the 4-Way like normal while stowing the adapter in the truck. The…

view full answer...

Answer 5

For a boat trailer, the best finish is going to be galvanized. The Kenda 5.70-8 Bias Trailer Tire with 8" White Wheel - 4 on 4 - Load Range C #AM30120 that you were looking at may work fine, but I don't recommend it for boat trailers since…

view full answer...

Answer 6

For as trashed as those brake assemblies are I am impressed with how spotless that spindle is! Based on the bearing numbers you mentioned you have a #84 spindle and the hub part #AKHD-545-35-G-K is correct. Since this its galvanized it's a really…

view full answer...

Answer 7

We cannot get the Atwood replacement parts as they went out of business several years ago. Only solution for you would be an all new coupler like the Demco part #DM72VR that you referenced for if you have drum brakes or part #DM62VR if you have disc…

view full answer...

Answer 8

Since the Lippert Hydrauluic Landing Gear Feet are 12 inch in diameter and round the correct Snappads would be the part #SP74FR4.

view full answer...

Answer 9

On a 4-Way flat trailer wiring harness, white is the ground, brown is running lights, yellow is left turn signal and green is right turn signal. It sounds like your trailer has a wishbone harness. A wishbone harness splits the running light circuit…

view full answer...

Answer 10

If it was a 4-pin connector with 5 wires then it is called a wishbone harness and would have 2 wires attached to the running light pin so you have one wire for each side of the trailer. Typically, on a 4-Way, the white wire is ground, brown is…

view full answer...

Answer 11

You have it right so far, the 4-way connector is just as you have stated. Remember that Yellow has a L in it so that is the left side brake/turn signal and green has a R in it so that is the right side brake/turn signal. The colors for wiring a 7-way…

view full answer...

Answer 12

The brown (running light) wires all run to each other as they carry the same circuit. The reason there is two browns on the trailer side is because there are running lights that are on both sides of the trailer. Aside from that all the rest of the…

view full answer...