Connecting Semi Tractor Truck Wiring to 5th Wheel RV Wiring

Updated 05/02/2019 | Published 05/01/2019

Products Featured in This Question

Roadmaster Brite-Lite 3-to-2 Tail Light Converter for Towed Vehicles

(130)

$55.72

Curt Echo Wireless Brake Controller - 7-Way Plug-in w/ Bluetooth App - Up to 2 Axles - Proportional

(1885)

$289.95

Question:

Hi. I am needing to connect my big truck to my fifth wheel camper. I tried making up my own cord before reading these q and a’s and I’m seeing now why my contraption didn’t work. The plug on my semi has turn signals and brake lights separate, whereas my trailer doesn’t. What exactly do I need in order to make this work? I have made up a cord with the correct ends, apparently it’s a converter or two that I need to supplement what I have.

asked by: Jay J

Expert Reply:

The Commercial truck plug will have the functions shown with the stop lamp separated from the turn signals as you stated. so you will need the Roadmaster Brite-Lite Wiring Converter # RM-732 to combine those signals for you to make them compatible with your 5th wheel trailer. You will only need this one converter. You will not connect anything to the clearance side marker pin and your 12V power will come from the Auxiliary power pin location. I recommend using the Tow Ready 5th Wheel/Gooseneck Pigtail Wiring Harness with 7-Way, RV-Style Connector - 4' Long # 20024 so you will have both wiring connectors ready to go at any time.

Since there isn't a brake controller output, I recommend using a hard mounted RV 7-way and then using the Curt Echo # C51180 for your braking system since you won't have that separate brake controller wiring unless you hardwire your adapter.

expert reply by: Jason S