How to Separate Out Running and Brake Combined Signals on a Multiplex Wiring System

Updated 09/12/2025 | Published 08/23/2025

Products Featured in This Question

Curt 2-to-3 Tail Light Converter for Towed Vehicles w/ Incandescent Tail Lights

(80)

$32.55

Load Resistor Kit for LED Turn Signals - 50 Watts - 6 Ohm - Qty 2

(37)

$13.64

Question:

Hi, I have a question about tail light wiring. I’m trying to wire separate LED brake and turn lights on my vehicle and my vehicle already has a separate turn signal wire and a combined brake/running light wire. However, the LED lights each have three wires turn, running, and ground for the amber turn light. Break, running, and ground for the brake light. How would I go about splitting the brake/running light wire from my vehicle to connect it to the LED lights?

asked by: Benjamin L

Expert Reply:

Hey Benjamin, thanks for reaching out!

It sounds like your vehicle has multiplex wiring so you need the ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat Trailer Connector and Installation Kit # 119250KIT. This takes all of the needed wiring circuits and splits them up into the standard trailer wiring 4-Way flat connector:

- Running
- Ground
- Left Stop/Turn
- Right Stop/Turn

The Curt 2-to-3 Tail Light Converter # C56196 will then allow you to separate out the brake and turn signals, but the Curt converter isn't designed for LED lights so you'll also need the Load Resistor Kit # DI34ZR so the LEDs will have enough power pull for the converter will work correctly.

Does this sound like it will do what you need it to do?

expert reply by: Jon G

Jon G.

9/12/2025

Hey Benjamin, did the wiring harness and converter setup work out for your LED lights? I'm asking because your experience could really help others with similar wiring challenges.