I have an all-in-one sort of trailer light I'm trying to mount to something (LED lights). It has 5 wires: running, left turn, right turn, ground, and brake.

My truck has a Flat 4 (ground, running, left, right) and 7 pin connectors.

What is the easiest way to wire up this light? Get a 4 way plug, and wire it to the 5 trailer wires- but how? Do I just leave the dedicated brake wire (LED brake lights, not trailer brake) off the harness and tape it up?

TIA for the advice, and apologies because I'm sure I'm missing something really simple.

Your 5 flat plug on your truck will be right turn, left turn,
running, ground and trailer surge brake release. If you don't have a surge brake don't use it.
The light should not have a brake wire as that's not needed. Perhaps the light has a back up light on it?

Just did an edit about the back up light.

The 5 wires are on the LED trailer light unit. 5 wires coming out the back of it. Labeled: running, left turn, right turn, ground, brake (if necessary).
No trailer brakes. I'm just trying to wire this single light unit into my truck.

The truck has a standard 4 way and 7 pin harness.

Well like a DA I read your post and you say your truck just had a flat four, not a five…. my bad. That would be ground, right, left and running. Just use those on your light. Leave off the back up light wire, or what they are calling brake. Most brake lights are done through the left and right turn wires.

Thanks so much! I appreciate it greatly!

I figured the OB would know better than some foreign labeled light.

Going to save this thread. Straight forward good info.

A couple of questions:

Can you share info on the exact light you're trying to wire up?

What colors are the wires you're dealing with?


Trailer wire standard colors should be as follows:

Running lights - brown
Right turn - green
Left turn - yellow
Ground - white
Battery positive (hot) - red or black
Electric trailer brakes - blue
Reverse lights - purple

https://www.amazon.com/Trailer-Sequential-Certified-Submersible-Trailers/dp/B07CZ6CQT7?ref_=ast_sto_dp&th=1

It's an amazon cheapo. LED light bar.

5 wires
Brown: ID/Running Light
Green: Right Turn Signal (Sequential, meaning the LED's light up in pattern)
Yellow: Left Turn Signal (Sequential)
White: Ground
Red: Brake Light 100% Red (if applicable)


Because it says "if applicable" I'm assuming that the dedicated brake light wire is not to be used on standard 4 ways, where the turn signal and brake light share the same wire.

I'm just going to run it as a regular 4 wire and see what happens. It's not mission critical for my application, so no biggie if it doesn't work.

S.A. Aggie said:

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Going to save this thread. Straight forward good info.

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Classic OB.
correct straight-forward info, maybe a little BS on the side.

Youtube it. There has to be 100+ videos of how to install trailer lights for a standard 4 pin plug lol. Visual would be much easier to work from.

Tractor Supply and probably Smazon sell
All sorts of adaptors so you don't need to swap plugs.

Bring it to me. I'll get it fixed up right. I work on and fix up tons of trailers every year. I have a trailer wiring method I developed for boat trailers to make those lights and wiring live longer. Boat trailers are notorious for trailer wiring issues.

I think most here are thinking the one labeled "brake" is a blue wire for surge brake release/by pass. That is not the case for this light.

As you know for your 4 flat you have ground, running, L, R. When you hit the brake pedal , the L and R are energized to illuminate both at once to show braking. That is how our vehicles are wired.

Hopefully won't need the one labeled brake but might need some experimentation and a test light to confirm.