bing tracking image
  1. Flat Tow Wiring Harness
  2. Roadmaster
  3. Diode Kit
  4. Splices into Vehicle Wiring
  5. Universal
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
In Stock
$255.53
Flat Tow Wiring Harness

Will this fit?

To see if this custom-fit item will work for you please tell us what vehicle you'll use it with.

Add to cart
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images

In Use/Installed

Need help with installation?
Locate installers near me
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.
  • All Info
  • Reviews (251)
  • Q & A (0)
  • Photos

Roadmaster Flat Tow Wiring Harness - RM38FR

  • Diode Kit
  • Splices into Vehicle Wiring
  • Universal
  • Roadmaster

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

250 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.

by:



by:



by:



by:



by:



by:



by:



by:



by:



by:



by:



by:



by:



by:



by:



by:



by:



by:



by:



by:



by:



by:



by:



by:



by:


25
250
Show More Reviews

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

  • Flat Towing Components And Requirements For A 2024 Chevy Equinox
    2024 models of the Chevy Equinox have the same steps listed as the 2023 models to get the vehicle ready to flat tow: 1. Position the vehicle to be towed and secure it to the towing vehicle. 2. Start the vehicle. 3. If equipped with AWD, engage the AWD system and confirm that it is on. 4. Move the shift lever to N (Neutral). 5. Then, put the vehicle into accessory mode by pressing ENGINE START/STOP one time without the brake pedal applied. An amber light will appear in the button when in...
    view full answer...
  • 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...
    view full answer...
  • Recommended Parts to Flat Tow a 2024 Chevy Equinox LT
    Yes, it can! The 2024 Chevrolet Equinox LT can indeed be flat towed. Here are the parts you will need to tow it behind your diesel pusher: Tow Bar and Safety Chains - Roadmaster Falcon 2 Tow Bar item # RM-520 and item # RM-643 Base Plate Kit - Roadmaster Direct-Connect Base Plate Kit - Removable Arms item # RM-523193-5 Wiring Harness - Roadmaster Diode 7-Wire to 6-Wire Flexo-Coil Wiring Kit item # RM38FR for LED lights or item # RM26FR for Incandescent Lights Battery Disconnect Switch...
    view full answer...
  • Recommended Base Plate and Flat Towing Parts for a 2023 Ford F-150 Tremor
    For your 2023 Ford F-150 Tremor, I recommend the Roadmaster Direct-Connect Base Plate Kit item # RM38VR. This kit has removable arms that are not only the easiest to connect a tow bar to but are completely removable. This will give your truck as close to a factory look as possible when removed. Some other parts you will need to flat tow your F-150 are listed below along with any installation videos we may have. Feel free to email me back if you have any other questions or concerns. Tow...
    view full answer...
  • Recommended Flat Towing Set Up for a 2023 Ford Bronco Pulled by a Motorhome w/ Air Brakes
    Congrats on the new motorhome! I was looking at the features that came with your 2024 Dynamax Dynaquest XL. It does not look like it came prepped for a flat towing set up so you're going to need the Demco Air Force One Flat Tow Brake System for RVs w/ Air Brakes item # SM99243. Now if you do end up having the BrakeSync set up you'll want the item # DM23MV you were looking at but I did not see it as an option. For a Blue Ox tow bar, I recommend the Blue Ox Alpha 2 Non-Binding Tow Bar item...
    view full answer...
  • Recommended Diode Kit for a 2021 Jeep Grand Cherokee Limited
    Hey Andy! The premium lighting group that Jeep offers for the 2021 Grand Cherokee Limited won't affect which diode wiring kit you need. The option that will determine the correct one is whether or not your Jeep has the Parksense Proximity Sensors. I have listed the parts below: Without Proximity Sensors - Roadmaster Diode 7-Wire to 6-Wire Flexo-Coil Wiring Kit item # RM-15267 or item # RM-152 for just the diodes With Proximity Sensors - Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit...
    view full answer...
  • Parts Needed to Flat Tow a 2021 Ford F-150 w/ a Roadmaster Falcon All-Terrain Tow Bar
    We can get you set up to flat tow your 2021 Ford F-150, and you will need a number of parts, including base plates, in order to do so, though you do already have one with the Roadmaster Falcon All Terrain, Non-Binding Tow Bar # RM-522. Along with the Roadmaster base plates you mentioned, the other things you will need are safety chains (if you don't have them), as well as a wiring kit, brake light relay, and supplemental braking system. I'll go ahead and list out the parts for you to make...
    view full answer...
  • Recommended Baseplate For A 2021 Chevy Equinox With Active Lower Air Shutters
    Hi Dean, The Curt Custom Base Plate Kit # C28FR is the only baseplate we have listed as confirmed fit for models with Lower Active Air Shutters. This baseplate is compatible with both Curt and Blue Ox tow bars. If you haven't picked out the rest of your flat towing components then I have the following recommendations: Tow Bar: Curt Rambler Non-Binding Tow Bar # C26FR Tow Bar Wiring Kit: For L, LS, LT models you'll want the Roadmaster Diode Wiring Kit # RM-15267. For Premier models you'll...
    view full answer...
  • Steps Needed To Get Your 2023 Chevy Equinox Ready To Flat Tow
    To get your 2023 Chevy Equinox ready to flat tow you'll need to complete the following steps: 1. Position the vehicle to be towed and secure it to the towing vehicle. 2. Start the vehicle. 3. If equipped with AWD, engage the AWD system and confirm that it is on. 4. Move the shift lever to N (Neutral). 5. Then, put the vehicle into accessory mode by pressing ENGINE START/STOP one time without the brake pedal applied. An amber light will appear in the button when in accessory mode. The...
    view full answer...
  • What Baseplate Do I Need To Flat Tow a 2024 Chevrolet Tahoe Premier?
    Hey James! I checked with our vendors and the correct baseplate for your 2024 Chevrolet Tahoe Premier is the Blue Ox item # BLU58FR. I have linked the installation instructions below and they specifically mention the Premier model right at the top of the first page. We actually installed this base plate on a 2024 Tahoe so I also added the link to it so you can see how to get it set up. Here are the rest of the parts you'll need to flat tow your 2024 Chevrolet Tahoe Premier. If you have...
    view full answer...
  • Recommended Flat Tow Setup For A 2024 Ford Maverick Hybrid
    Hello Robert. For flat towing your new 2024 Ford maverick Hybrid I recommend the Roadmaster Direct-Connect Base Plate Kit # RM97RR. Most of the Maverick base plates will install fairly similarly, and you will be fully removing the front bumper for installation. I like the Roadmaster base plates for a few reasons. The custom fitted brackets make installation straightforward, the twist lock arms are convenient and easy to use, and the base plate has pre-welded attachments for your electrical...
    view full answer...
  • Recommended Tow Bar Wiring Kit For Flat Towing A 2024 Ford Bronco
    Hey Gary, For the wiring you'll need the Roadmaster Diode 7-Wire to 6-Wire Flexo-Coil Wiring Kit # RM-15267. This will transfer your motorhome's traffic signals to the tail lights of your Bronco. If you find that you have variable voltage tail lights (one wire used for the signals instead of separate wires) then you'll need part # RM38FR for LED lights or # RM26FR for incandescent. If you haven't pick out the rest of your flat towing components then I have the following recommendations...
    view full answer...
  • Recommended Flat Towing Parts for a 2024 Ford Bronco Wildtrack
    The Second Vehicle Kit item # SM99209 does not come with the coach link transmitter. You'll need to purchase it separately with the Demco Wireless Coachlink Braking Monitor item # SM99945. As far as a high low adapter goes, that's going to require you to take a couple of measurements. In order to be considered level your RV's hitch has to be within 3" up or down to the base plates on your 2024 Bronco Wildtrack. I do not have specific measurements of your vehicle or have any way of knowing...
    view full answer...
  • Recommended Flat Towing Parts for a 2023 Chevy Trailblazer
    Since you already have a Blue Ox tow bar you will want the Blue Ox Base Plate Kit item # BLU49FR. This kit is confirmed to fit all models of the 2023 Trailblazer, RS, L, LS, LT, and ACTIV. This base plate has removable arms that will work with most Blue Ox tow bars. Here are some other parts you will need to flat tow your 2023 Chevy Trailblazer: Safety Chains - Roadmaster item # RM-643 Wiring Harness - Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit for Variable Voltage Incandescent...
    view full answer...
  • Recommended Flat Towing Set Up for a 2023 Chevy Trailblazer
    Hey Richard! To flat tow your 2023 Chevy Trailblazer you will need the following parts: Tow Bar and Safety Chains - Roadmaster Falcon 2 Tow Bar item # RM-520 and item # RM-643 Base Plate Kit - Roadmaster Direct-Connect Base Plate Kit - Removable Arms item # RM35FR if you have the L, LS, LT, or ACTIV models or item # RM46VR if you have the RS model Wiring Harness - Roadmaster Diode 7-Wire to 6-Wire Flexo-Coil Wiring Kit item # RM26FR if you have the L, LS, or LT models or item # RM38FR...
    view full answer...
  • Recommended Flat Towing Parts for a 2024 Chevrolet Equinox
    I would be happy to! To flat tow your 2024 Chevy Equinox RS you will need the following parts: Tow Bar and Safety Chains - Roadmaster Falcon 2 Tow Bar item # RM-520 and item # RM-643 Base Plate Kit - Roadmaster Direct-Connect Base Plate Kit - Removable Arms item # RM-523193-5 Wiring Harness - Roadmaster Diode 7-Wire to 6-Wire Flexo-Coil Wiring Kit item # RM38FR for LED lights or item # RM26FR for Incandescent Lights Charge Line - Roadmaster Battery Charge Line Kit for Towed Vehicles...
    view full answer...
  • Roadmaster Base Plate Kit for 2025 Chevrolet Trax
    Hey Charlene! Roadmaster actually does make a base plate for your 2025 Chevy Trax. If you do not have the ACTIV trim level you need the Roadmaster Direct-Connect Base Plate Kit # RM25EQ and if you have the ACTIV trim you need the # RM25DQ. Both will work with your Roadmaster Falcon 2 so you won't need a new tow bar. Do you have the rest of your setup already? You will also need the following: -Roadmaster Smart Diode Kit for Variable Voltage Incandescent Tail Lights - 7-to-6-Way Adapter...
    view full answer...
  • Looking For Blue Ox Base Plate For 2025 Chevy Trax For Recreational Flat Towing
    Hello Stephen, thanks for reaching out. Yes, there is a Blue Ox base plate available for the 2025 Chevy Trax. There are different part numbers depending if your vehicle has the ACTIV feature, so please choose from the following: - Blue Ox Base Plate Kit - Removable Arms # BLU99HR (ACTIV models) - Blue Ox Base Plate Kit - Removable Arms # BLU24UR (Excluding ACTIV models) Are you needing the rest of the parts for your flat tow setup? If so, here is what I recommend: - etrailer SD Non-Binding...
    view full answer...
  • Complete Flat Tow Setup for 2024 Chevy Trax
    Hey Dennis, thanks for reaching out. I can definitely help you with a flat tow setup for your 2024 Chevy Trax. I love the decorations on your Jayco RV by the way. USA! I will start with a parts list, followed by a few notes about flat towing your Trax. Here is what I recommend: - Demco Tabless Base Plate Kit - Removable Arms # DM59YV - etrailer SD Non-Binding Tow Bar - RV Mount - 2" Hitch - 6,000 lbs # e34ZR - Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights - 7-Way to...
    view full answer...
  • Recommended Flat Towing Wiring Harness for a 2023 Ford F-150 w/ LED Lights
    No, it will not. Since your 2023 Ford F-150 has LED tail lights you will need the Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit for Variable Voltage LED Tail Lights item # RM38FR. The issue is that the brake and running lights will all be the same brightness with the standard diodes included in the Demco item # DM9523010-54. The diodes in the Roadmaster item # RM38FR kit convert the 12V signal from your RV's wiring to a 9V signal which allows the differentiating brightness needed between...
    view full answer...
  • Diode Wiring Kit For Flat Towing A 2022 Ford F-150
    We don't currently offer the Hopkins 56012 wire harness so you would need to purchase it through Hopkins or you could use the Roadmaster # RM38FR (LED tail lights) or # RM26FR (Incandescent tail lights) instead.
    view full answer...
  • Recommended Base Plate for a 2023 Ford Bronco Being Towed by a Demco Dominator Tow Bar
    The best base plate for your 2023 Ford Bronco is the Roadmaster Direct-Connect Base Plate Kit item # RM92ZR. You will need to use the Demco Tow Bar Adapter Kit item # DM9523032 to connect it to your Demco Dominator item # DM9511008. There is a Demco base plate item # DM76GV but it only works with the plastic bumpers. The Roadmaster is compatible with your steel one. Some other parts you will need to flat tow your 2023 Bronco are listed below: Tow Bar Wiring Kit - Roadmaster Diode 7-Wire...
    view full answer...
  • Recommended Parts to Flat Tow a 2021 Chevy Tahoe Premiere
    I would be happy to! To flat tow your 2021 Chevy Tahoe Premiere you will need the following parts: Tow Bar and Safety Chains - Roadmaster Sterling Tow Bar item # RM-576 Base Plate Kit - Roadmaster Direct-Connect Base Plate Kit - Removable Arms item # RM59VR Battery Disconnect - Roadmaster Battery Disconnect with Switch item # RM-766 Wiring Harness - Roadmaster Diode 7-Wire to 6-Wire Flexo-Coil Wiring Kit for LED's item # RO44FR or Item # RO94FR for Incandescent Lights Supplemental...
    view full answer...
  • Recommended Flat Towing Parts for a 2023 Ford Bronco Badlands w/ a Capable Bumper
    The recommendation would not change because the base plates install in the same location on both the modular and capable bumpers. Same with a potential lift. Something like that would be addressed down the road with a high low adapter if necessary. To flat tow your 2023 Ford Bronco Badlands with a capable bumper you will need the follow parts: Tow Bar and Safety Chains - Roadmaster Falcon 2 Tow Bar item # RM-520 and item # RM-643 Base Plate Kit - Roadmaster Direct-Connect Base Plate...
    view full answer...


< Previous
123. . .6




Info for this part was:

Employee Lindsey S
Written by:
Lindsey S
Employee Jameson C
Expert Research:
Jameson C
Employee Joshua S
Video Edited:
Joshua S
Employee Jacob T
Video Edited:
Jacob T
Employee Dustin K
Video Edited:
Dustin K
Employee Jonathan Y
Video Edited:
Jonathan Y
Employee John S
Video Edited:
John S
Employee Chris R
Video by:
Chris R
Employee Ethan H
Video by:
Ethan H
Employee Kyle M
Video by:
Kyle M
Employee Wilson B
Updated by:
Wilson B
Employee Mike S
Updated by:
Mike S
Employee Amanda K
Updated by:
Amanda K
Employee Shane H
Test Fit:
Shane H
Employee Jacob H
Test Fit:
Jacob H
Employee Ryan G
Test Fit:
Ryan G
Employee John A
Test Fit:
John A

At etrailer.com we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time.


<