bing tracking image
  1. Tow Bar Wiring
  2. Roadmaster
  3. Diode Kit
  4. Splices into Vehicle Wiring
  5. Universal
Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit for Variable Voltage LED Tail Lights

Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit for Variable Voltage LED Tail Lights

Item # RM38FR
Our Price: $213.21
Tow Bar Wiring

Will this fit?

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

Shipping Weight: 5 lbs
Add to cart
In Stock
RM38FR - Universal Roadmaster Splices into Vehicle Wiring
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
This complete kit includes everything you need to connect your RV's tail, brake, and turn signal lights to your vehicle with variable voltage lights while flat towing. 7-Wire to 6-wire cord and 6-way car-side socket included for easy hookup. Great Prices for the best tow bar wiring from Roadmaster. Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit for Variable Voltage LED Tail Lights part number RM38FR can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
  • All Info
  • Reviews (23)
  • Q & A (0)
  • Photos

Roadmaster Tow Bar Wiring - RM38FR

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

This complete kit includes everything you need to connect your RV's tail, brake, and turn signal lights to your vehicle with variable voltage lights while flat towing. 7-Wire to 6-wire cord and 6-way car-side socket included for easy hookup.


Features:

  • Complete wiring kit lets you connect your RV's tail, brake, and turn signal lights to your towed car's lighting system
  • Smart diodes ensure that your variable voltage, LED tail lights function as they should while your car's being towed
    • Converts the 12V signal from your RV's wiring to a 9V signal so your tail lights work as intended
    • Prevents electrical feedback that can damage your vehicle's electrical components
  • 7-Wire to 6-wire Flexo-Coil adapter cord lets you easily run power from your motorhome to your towed vehicle
    • Expands out to 8' to prevent dragging and tangling
    • Resistant to water, oil, and chemicals and has silicone-injected plugs to prevent corrosion
  • 6-Way socket wires to harness and mounts on towed car with included bracket
  • Powder coated aluminum casing on diodes is corrosion resistant and provides protection from the elements
  • Kit includes 2 smart diodes, wiring harness, split loom, ring terminals, zip ties, 7-wire to 6-wire adapter cord, 6-way socket with mounting bracket, and 10' of 14-gauge wire
  • Brake light relay (RM-88400 - sold separately) may be required if used with supplemental braking system
  • Assembled in the USA


Specs:

  • 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 cord max length: 8'
  • Coiled cord retracted length: 15"
  • Limited lifetime warranty


This complete smart diode wiring kit lets you connect your RV's tail, brake, and turn signal lights to your towed car's lighting system so that you'll have the signal lights necessary for flat towing your vehicle.


Because your vehicle has variable voltage tail lights, you cannot use a standard diode wiring kit to get these signal lights. If regular diodes are used on a vehicle that has variable voltage tail lights, the bulbs will light up as though the towed car is braking whenever the tail lights are on. In other words, there will be no difference between your vehicle's brake lights and running lights. This is because variable voltage tail lights use the same wire to power both the brake lights and tail lights. They do this by using a 12-volt signal for brake lights and a 9-volt signal for tail lights.


Smart diodes correctly modulate the 12-volt signal coming from your RV to activate only the intended circuit. The result is that your vehicle's tail lights will look and function as intended.


This wiring kit includes everything you need to hook up your motorhome's electrical to your towed car. It is designed to work with LED lights only. If your vehicle has incandescent lights, you'll need to use the smart diode kit designed for incandescent tail lights (RM26FR - sold separately) instead.


If your RV has separate tail light wiring, wherein the brake and turn signals run on separate wires, you'll need a wiring converter (RM-732 - sold separately) to complete this installation.


Smart Diode Wiring Diagram


153789 Roadmaster 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




Customer Satisfaction Score:


Customer Reviews

Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit for Variable Voltage LED Tail Lights - RM38FR

Average Customer Rating:  4.8 out of 5 stars   (23 Customer Reviews)

This complete kit includes everything you need to connect your RV's tail, brake, and turn signal lights to your vehicle with variable voltage lights while flat towing. 7-Wire to 6-wire cord and 6-way car-side socket included for easy hookup.

by:
Chevrolet Equinox

I purchased this as part of a package which included; Hitch and wiring for my 2022 Equinox, Base plate, Tow Bar, brake System and connecting air hose, break away cables, LED tow lights with wiring harness, and a trickle charger to keep the Equinox battery from going dead while I was towing it behind my class A RV.
I had etrailer do the install of all the components on my car and RV. All the workmanship was excellent and done in the amount of time they said it would take. Also because they did not have a video of this equipment being put on this year and model vehicle, I gave them permission to make a video(which added a extra day and a half to the install)and the installation was free. Everything has worked perfectly and I couldn't be happier. Etrailer is my go to for anything towing and also RV parts.



by:

Works well and east to install just time consuming for layout, placement and overall cleanliness for super SANO install. The timing of installing this and the DUO Plug in Play must be done simultaneously. Layout the DUO first for placement locations and wire runs then this lighting wire run from front connection to rear area, then start at the front and make the connections from front to rear in one pass. Worked perfectly first time. Install fuses last.



by:

I ordered an in stock item on Thursday but did not receive it until 9 days later. Maybe I didn't order it correctly to receive it sooner. I don't think a picture will show the products on my vehicle. That is a great thing!



by:
2022 Ford F-150



by:



by:



by:



by:
2020 Lincoln Navigator



by:



by:

A very easy installation. The instructions and kit quality were very good. I installed this kit on a 2019 Chevy Spark that I tow behind an RV. The lights have never failed to work as expected. I would highly recommend this product.



by:

Great product!!



by:

Works like towing a trailer, The wiring was a challenge and the E-Trailer video on installatios was very helpful



by:

This is to rig my third vehicle for flat towing behind our motorhome. I am sure that the e-trailer people will be available to help me if I need advice.



by:

Great service .I had a problem with a part they sent a new one and it worked great.Would recommend.



by:

Installation went very well with the help of the video on your website. Thanks.



by:

Work as advertised - no issues



by:



by:



by:



by:



by:



by:



by:


23
23

See what our Experts say about this Roadmaster Tow Bar Wiring

  • 2021 Chevy Trailblazer LED diode wiring
    Using the Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit for Variable Voltage LED Tail Lights Item # RM38FR you'll want to cut the diodes in just before the the twist-lock to the LED and another just before the incandescent bulb. The point of the diode is to stop power from reversing and damaging the wire behind it so being closer to the bulbs will help save wire in the event that there is a power surge. Hooking up diodes to your car will not cause the LED or signal lamp to act any...
    view full answer...
  • Tow Bar Lighting Kit for 2019 Ford Expedition with LED Brake Lights
    For your 2019 Ford Expedition with LED taillights the Roadmaster diode kit part # RM-15267 is the best option that we've had the chance to install on an Expedition just like yours. See attached install video link for more info. There is no issue installing this kit on a vehicle with LED taillights like yours either.
    view full answer...
  • Does The 2023 Ford Edge Require Smart Diodes?
    The 2023 Ford Edge ST has variable voltage tail lights, so a smart diode kit will be required. For that we recommend the Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit # RM38FR. This is a full wiring kit so you get your diodes, wire, a 6 pin plug, and your coiled cable to connect the towed vehicle to your coach.
    view full answer...
  • Flat Tow Lighting Solution for 2023 Ford Bronco Badlands with LED Taillights
    There's actually a much simpler solution for wiring your 2023 Ford Bronco with LED taillights to be flat towed with the Roadmaster smart diode kit part # RM38FR.This will wire your separate taillight circuits to function like a combined setup when flat towed which is perfectly safe, legal, and acceptable. Sometimes people do wire up their separate setups to work the same as the vehicle but it's honestly a lot more money and work than it's worth so I would not recommend that route for your...
    view full answer...
  • Flat Tow Wiring For 2023 Ford Bronco Outer Banks
    The flat tow wiring for your 2023 Ford Bronco Outer Banks is the same product you will use to get wiring to the front of your vehicle. The correct wiring harness is going to depend on if you have LED or incandescent lights on your Bronco: - LED Lights: Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit # RM38FR - Incandescent Lights: Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit # RM26FR
    view full answer...
  • How To Determine If Your 2023 Ford Bronco Has Variable Voltage Tail Lights And What Diodes To Use
    Variable voltage tail lights use the same wire for the brake signal and running lights instead of the standard turn/brake wire setup. To determine if you have variable voltage tail lights you'll need to pull the tail light out to get to the wiring and test wires with a probe tester # PTW2993 in order to see if the same wire powers both the running lights and brakes. If you do have variable voltage LED tail lights then you'll need the Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit...
    view full answer...
  • Diode Tow Bar Lighting Kit that Fits 2015 Ford Edge Hybrid with LED Taillights
    I checked with Roadmaster on this and found out that the hybrid versions of your 2015 Ford Fusion with the LED taillights require a different diode setup which is why you are experiencing the problems you've mentioned using the # RM-154. So instead you would need the diode kit part # RO44FR for just the diodes and wiring or part # RM38FR for the kit that includes the coiled tow bar wiring and connectors.
    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...
  • 2024 Ford Maverick Wiring Needed for Flat Towing Behind a Motorhome
    I recommend using the Roadmaster wiring for your 2024 Ford Maverick because I've found it to be the most reliable on the market. The correct kit depends on if your Maverick has LED lights or not: - LED Lights # RM38FR - Non-LED Lights # RM-15267 The battery on your vehicle will also drain while towing so I recommend installing the Battery Charge Line Kit # RM-156-25 to prevent that from happening. Attached are some installation videos for you to check out
    view full answer...
  • How To Install Diode Tail Light Wiring In A 2020 Chevy Equinox
    A 2020 Chevy Equinox can't use a standard diode kit like the # RM-154 and would instead need smart diodes like the # RM26FR (incandescent) or # RM38FR (LED). These vehicles have variable voltage wiring so using a standard diode wouldn't allow the lights to properly display the signals form your 2019 Jayco Alante 26X. For the installation you'll just need to determine if the motorhome has separate or combined tail light wiring to determine the correct wiring procedures. In a combined system,...
    view full answer...
  • Comparing Roadmaster and Blue Ox Base Plate Kits For 2021 Ford F-150 4WD
    If I was installing a base plate kit on my 2021 Ford F-150 4WD to flat tow it I personally would go with the Roadmaster Direct-Connect Base Plate Kit # RM38VR over the Blue Ox # BLU33FR. This is simply due to preferring the Roadmaster tow bars over the Blue ox options, though both brands are well known and very reliable so you really cannot go wrong with either option especially since both of these above base plate kits install in a very similar manner, and both have removeable arms so...
    view full answer...
  • Is Brake Light Switch Needed w/ Invisibrake Supplemental Braking System on 2021 Chevy TrailBlazer
    It looks like you've got a good handle on what you need to flat tow your TrailBlazer. You will indeed need a stop light switch, part # RM62FR. Also, per the owner's manual, you'll need to disconnect the negative battery terminal before towing. A quick disconnect, part # RM-766 is available. The kit includes a switch that mounts in the passenger cab of the vehicle that allows you to disconnect and connect the battery remotely without needing to go into the engine compartment and disconnect...
    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 Parts to Flat Tow a 2023 Ford F-150 Hybrid
    You don't need another truck. To flat tow your Hybrid 2023 Ford F-150 you need the parts listed below: 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 # RM38VR Wiring Harness - For LED Lights - Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit for Variable Voltage LED Tail Lights item # RM38FR or for Incandescent Lights - Roadmaster Smart Diode 7-Wire to 6-Wire Wiring...
    view full answer...
  • Does Roadmaster Flat Towing RM-155 Bulb and Socket Kit Fit a 2020 Chevy Equinox
    It will depend on the trim level of your 2020 Equinox. If it's an L, LS or LT model, you will be able to use the # RM-155 Roadmaster bulb and socket kit. If it's a Premier model, you'll need to use a different option. The Premier model uses variable voltage taillights that would require a smart diode. If the taillights on the Premier model are incandescent, use # RM26FR. If they're LED, use # RM38FR. I've linked to some installation videos that you might find helpful.
    view full answer...
  • Recommended Tow Bar Wiring Kit For Flat Towing A 2022 Ford Bronco
    The Curt Tow Bar Extension Cord w/ Socket # C59HR is just the parts that will go between the motorhome and vehicle. If you're setting the vehicle up to flat tow then you'll want to go with a kit like the # RM-15267, which will have everything you need to have the tail lights of the Bronco properly display the motorhome's traffic signals. If the Bronco has variable voltage tail lights then you'll need to use part # RM38FR for LED's or part # RM26FR for incandescents.
    view full answer...
  • How to Find Tail Light Functions on 2023 Chevy Equinox Premier for Flat Tow Light Wiring
    Thanks for reaching out! The correct wiring harness for flat towing your 2023 Chevy Equinox Premier will be the Smart Diode kit from Roadmaster. You need part # RM26FR if you have incandescent tail lights or part # RM38FR if you have LED tail lights. To determine the correct wires to splice into you need to remove the clip from the tail light and then use a circuit tester like part # PTW2992 to check what functions are on each pin. Unfortunately we don't have a pin-out of what functions...
    view full answer...
    Image 1 for Image 2 for
  • Wiring For Flat Towing 2022 Chevy Equinox LT
    Your 2022 Chevy Equinox LT requires flat tow wiring with smart diodes because your Chevy's tail lights have variable voltage, which means there is just one wire that sends different voltage to the lights based on if the brake lights or turn signals are on. The smart diodes regulate that voltage to ensure the correct signal is received. The right kit is going to depend on if your Equinox has LED or incandescent tail lights: - LED: Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit for Variable...
    view full answer...
  • Blue Ox Diode Wiring Kit Compatibility With A 2023 Ford Bronco
    The Blue Ox Tow Bar Wiring Kit - 4 Diodes # BX8848 is just a standard diode kit so it would work as long as you don't have variable voltage lighting. For variable voltage LED's you'll need part # RM38FR and for variable voltage incandescent bulbs you'll need part # RM26FR. If you do end up being able to use # BX8848 then you'll also need a 6-pole socket and 7-pole to 6-pole adapter, which you can get with part # BX88206.
    view full answer...
  • Is Roadmaster Smart Diode Kit Required for a 2020 Ford Edge ST
    To flat tow your 2020 Ford Edge you will need "smart diodes" as included in the Roadmaster # RO44FR Universal Kit. However, I would go ahead and get the Roadmaster # RM38FR kit that additionally includes the 7-way to 6-way cable and connectors that you will also need. Additionally, your Edge will drain its battery while being towed. I recommend the RM-766 battery disconnect unless you want to manually wrench the battery cables off every time that you unhitch and rehitch! Flat towing...
    view full answer...
  • Troubleshooting Loss Of Tail Light Function After Installing A Diode Kit In A 2023 Ford Bronco
    A 2023 Ford Bronco would only need to use smart diodes if it has variable voltage tail lights. Variable voltage tail lights use the same wire for the brake signal and running lights instead of the standard turn/brake wire setup. To determine if you have variable voltage tail lights you'll need to pull the tail light out to get to the wiring and test wires with a probe tester # PTW2993 in order to see if the same wire powers both the running lights and brakes. If you do have variable voltage...
    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...
  • Best Flt Tow Wiring Kit for a 2023 Ford F-150 Hybrid with LED Lights
    Since your 2023 Ford F-150 has the LED lights I highly recommend the Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit # RM38FR which has better diodes to make it compatible with the LED lights. The Demco Kit # DM9523010-54 has some really basic diodes which is why I recommend the Roadmaster over this. Demco doesn't list out fitment with LED lights but Roadmaster has a few diode kits and they say this newer one needs to be used for your truck. You'll also need the Charge Line Kit # RM-156-25...
    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...

Do you have a question about this Tow Bar Wiring?


Info for this part was:

Employee Lindsey S
Written by:
Lindsey S
Employee Jameson C
Expert Research:
Jameson C
Employee Joshua S
Video by:
Joshua S
Employee Chris R
Video by:
Chris R
Employee Jacob T
Video Edited:
Jacob T
Employee Dustin K
Video Edited:
Dustin K
Employee Mike S
Updated by:
Mike S
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. Let us know if anything is missing or if you have any questions.