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  1. Flat Tow Wiring Harness
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  4. Splices into Vehicle Wiring
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Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights - 7-Way to 6-Way Adapter Cord
Roadmaster

Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights - 7-Way to 6-Way Adapter Cord

Part Number: RM38FR
$261.34
Flat Tow Wiring Harness

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Smart diodes are our favorite option for getting brake and turn signals on your towed car. They are really well-made and reliable, plus pretty easy to install. This complete kit includes everything you need for multiplex LED tail lights. 1-800-940-8924 to order Roadmaster flat tow wiring harness part number RM38FR or order online at etrailer.com. Free expert support on all Roadmaster products. Great prices and Fastest Shipping for Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights - 7-Way to 6-Way Adapter Cord. Flat Tow Wiring Harness reviews from real customers.
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Roadmaster Flat Tow Wiring Harness - RM38FR

  • Diode Kit
  • Splices into Vehicle Wiring
  • 7 Blade to 6 Round
  • Roadmaster
  • Universal Fit

Smart diodes are our favorite option for getting brake and turn signals on your towed car. They are really well-made and reliable, plus pretty easy to install. This complete kit includes everything you need for multiplex LED tail lights.


Features:

  • Smart diodes correctly display RV's brake and turn signals on your towed car with variable voltage LED tail lights
    • Converts the 12V signal from your RV to a 9V signal so your tail lights work as intended
    • Prevents feedback that can damage your vehicle's electrical components
    • Keeps the battery from draining while flat towing
    • Resists corrosion with powder coated aluminum casing
  • 7-Way to 6-way coiled adapter cable runs power from your motorhome to your towed vehicle
    • Coiled to prevent dragging and tangling
    • Resistant to wear and tear with durable vinyl casing
  • 6-Way socket hardwires to towed car and mounts with included bracket
  • Kit includes:
    • 2 Smart diodes
    • 4-Wire harness
    • 7-Way to 6-way coiled adapter cord
    • 6-Way socket with mounting bracket
    • Butt connector, split loom, ring terminals, zip ties, and installation hardware
  • Assembled in the USA


Specs:

  • Application: variable voltage tail lights with LED bulbs only
  • Maximum amperage: 5 amps
  • Maximum voltage: 16 volts
  • Wiring harness length: 27'
  • 14-Gauge wire length: 10'
    • Maximum power rating: 60 volts
    • Operating temperature: 40 F to 176 F
  • Coiled cable:
    • Max length: 8'
    • Compressed length: 15"
  • Limited lifetime warranty


Notes:

  • A brake light relay (RM-88400 - sold separately) may be required if used with a flat tow brake system. (See below.)
  • If your motorhome has a separate lighting system, where the brake and turn signals run on separate wires, you'll need a tail light wiring converter (RM-732 - sold separately) to complete this installation. (See below.)

review for diode kit

"Don't be intimidated by diodes: if you can strip and crimp wire, this installation will be no problem."


What are Variable Voltage Tail Lights?

A variable voltage tail light (also known as multiplex) uses the same wire for both the brake light and the tail light, sending a 12-volt signal to the brake light and a 9-volt signal to the tail light. This works fine when you're driving, but when you are flat towing, the RV will send a 12-volt signal to both the brake light and tail light, making them the same level of brightness and impossible to distinguish from each other. The drivers behind you won't be able to tell the difference between your tail lights and your brake lights, which is a huge safety issue.


These smart diodes solve that problem by simply converting the signal from the RV to the lower voltage needed for your car's tail lights. They install permanently, but don't worry; everything will work as normal when you're not flat towing.


What if I Have Incandescent Tail Lights?

This kit is designed to work with LED lights only, so if you have incandescent variable voltage lights, you'll need kit RM26FR (sold separately) instead.


Do I Need a Brake Light Relay?

If the engine is off and your car's brake lights illuminate when you press the brake pedal, you need to install a brake light relay (RM-88400 - sold separately) with this kit. Without a relay, your car's brake signal will override the turn signal sent by the RV when you are slowing down to make a turn, creating a potentially dangerous situation. Other drivers will see that you're slowing down, but not that you're making a turn. With a brake light relay, you can signal both and travel safely.


Combined Lighting System vs Separate Lighting System

Combined vs Seperate Lighting System

A combined lighting system, or 2-wire system, uses the same light bulb to signal both braking and turning. (In other words, the car signals a turn by flashing the brake light.)


A separate lighting system, or 3-wire system, has the brake signal and the turn signal light up independently of each other. Typically, the turn signal is amber.


If your motorhome has a separate lighting system, add a tail light wiring converter (RM-732 - sold separately) to keep your setup functioning properly.



Wiring Diagram for Roadmaster Smart Diode Kit

Smart Diode Wiring Diagram


153789 Road Master Wiring Kit w Smart Diodes for LED Bulbs

02427 14-Gauge Brown Primary Wire

146-7 Roadmaster Adapter 7 to 6 Wire Flexo-Coil Cord

Installation Details RM38FR Installation instructions

This Product Fits The Following Vehicles



California residents: click here


Customer Satisfaction Score:

Ratings & Reviews

4.7

323 reviews
Smart diodes are our favorite option for getting brake and turn signals on your towed car. They are really well-made and reliable, plus pretty easy to install. This complete kit includes everything you need for multiplex LED tail lights.

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Show More Reviews

See what our Experts say about this Roadmaster Flat Tow Wiring Harness

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  • Blue Ox Base Plates & Wiring For Flat Towing 2023 Chevy Equinox Behind Motorhome
    Hi there Eddie; thanks for the question and we can get your 2023 Chevy Equinox equipped with a Blue Ox base plate and the needed wiring so you can flat tow it behind your motorhome. There are a couple of options for the wiring depending on the type of lights you have, so I'll go ahead and list out what you need to make it easier to determine. Base Plate: Blue Ox Base Plate Kit # BX1730 Wiring (If you Have LED Tail Lights): Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit for Variable...
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    Hey Brian. Sorry but there are no plug in wiring harnesses for flat towing your 2024 Ford Bronco Outer Banks. You'll need the Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit for Variable Voltage LED Tail Lights item # RM38FR. This wiring kit lets you connect your RV's tail, brake, and turn signal lights to your Bronco's lighting system. The smart diodes make sure that your LED tail lights function correctly while your Bronco's being towed. Here are some other parts you will need to...
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