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Roadmaster 4-Diode Universal Wiring Kit for Towed Vehicles - 4-Pole Flat Connectors

Roadmaster 4-Diode Universal Wiring Kit for Towed Vehicles - 4-Pole Flat Connectors

Item # RM-154
Our Price: $89.89
You Save: 38%
Tow Bar Wiring

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This wiring kit carries your RV's brake and turn signals to your towed car's tail lights. Diodes prevent electrical feedback. Towed car's tail lights will operate as a combined lighting system. 4-Pole wiring harness included. Great Prices for the best tow bar wiring from Roadmaster. Roadmaster 4-Diode Universal Wiring Kit for Towed Vehicles - 4-Pole Flat Connectors part number RM-154 can be ordered online at or call 1-800-940-8924 for expert service.
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Roadmaster Tow Bar Wiring - RM-154

  • Diode Kit
  • Splices into Vehicle Wiring
  • Tail Light Mount
  • Universal
  • Roadmaster

This wiring kit carries your RV's brake and turn signals to your towed car's tail lights. Diodes prevent electrical feedback. Towed car's tail lights will operate as a combined lighting system. 4-Pole wiring harness included.


  • Carries your RV's tail, brake, and turn signals to your towed car
    • Wires towed car as combined lighting system
  • Prevents feedback that can damage your vehicle's electrical components with diodes
  • Includes:
    • 4 Hy-Power diodes
    • (2) 4-wire harnesses with 4-pole flat connectors
    • Wire connectors, zip ties, and plastic loom
    • 1 Ring terminal


  • Max amperage: 85 amps
  • Max voltage: 24 volts
  • Power cord: 6' long
  • 4-Wire harness: 30' long
  • Plastic loom: 3' long



  • A brake light relay (RM-88400 - sold separately) may be required if used with a flat tow brake system. (See below.)
  • A wiring converter (118158 - sold separately) and 2 additional diodes will be needed to retain separate turn and brake signals. (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."

    Combined Lighting System vs Separate Lighting System

    Combined vs Seperate Lighting System

    A combined lighting 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 has the brake signal and the turn signal light up independently of each other. Typically the turn signal is amber.

    To keep the separate lighting system on your car functioning properly while you're flat towing, add a wiring converter (118158 sold separately) and 2 additional diodes.

    Do I Need a Brake Light Relay?

    If your towed car's brake lights illuminate when you press the brake pedal with the engine off, 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.

    Wiring Diagrams for Roadmaster Diode Kit

    Diode Wiring Diagram

    Diode Wiring Diagram

    Diode Wiring Diagram

    Diode Wiring Diagram

    154 Roadmaster Universal Wiring Kit with 4 Hy-Power Diodes

    Compare to Tow Ready TR118821

    Installation Details RM-154 Installation instructions

    This Product Fits The Following Vehicles

    Customer Satisfaction Score:

    Customer Reviews

    Roadmaster 4-Diode Universal Wiring Kit for Towed Vehicles - 4-Pole Flat Connectors - RM-154

    Average Customer Rating:  4.8 out of 5 stars   (766 Customer Reviews)

    This wiring kit carries your RV's brake and turn signals to your towed car's tail lights. Diodes prevent electrical feedback. Towed car's tail lights will operate as a combined lighting system. 4-Pole wiring harness included.


    It does what it says on the tin. Easily lit up my XJ so I could tow it. Only regret is that by making the connections at the rear, you don’t get the front market lights on the toad. I should have connected the running lights diode in the harness under the dash so all the marker lights come on at night.


    I’m always extremely satisfied with Roadmaster products. I had just bought a new truck and planned on towing it so I needed everything to get it ready to tow. This review also applies to to the other items I purchased.


    I thought I order the 7 to 6 pin wiring harness for my vehicle as I have the 7/6 cord I used when I pulled my pickup. I also ordered the 6 pin mounting bracket with the 6 pin adapter that wires into the harness. I received the kit which is a flat 4 pin harness.

    2015 Subaru Forester

    etrailer is a great company for towing products. They have fast delivery and they have nice installation videos. This order I added 2 more diodes to wire my 2015 Subaru Forester to have separate wiring for break, running, and turn signal lights.


    First of all Justin B,was awesome so very helpful and knowledgeable went over everything with me and then double checked what was needed before I placed the order for my 2022 maverick to be flat towed, order only took 3days to get to Fl.Kudos to Justin B all the guys putting together the order
    and etrailer awesome job,will definitely use them again for any of my needs.


    Works perfectly and straightforward instructions made it easy to install.


    This system worked perfectly from experience. They help from trailers e trailer agents was crucial for guiding me through the process.

    2014 Chevrolet Equinox

    It is exactly as advertised, not yet installed but looks pretty self explanatory




    Items arrived right on schedule and in good order. I ordered three items in the last few weeks. Their CHAT agents were extremely helpful in answering all my questions about compatibility with my vehicle.



    Diodes were not the ones I needed even though the etrailer site said they were. I had to purchase the correct ones from the auto electric shop where I had the wiring done.

    Etrailer Expert

    Jenny N.


    @Kenneth Honestly, I am surprised that the diodes did not work for you. I am curious as to if the installer explained why they would not work for you. What the reason was?


    I have order several things from etrailer. Their products are great. Due to nobody's fault but my own I ordered some wrong things. The return was so easy, no questions asked. I would recommend this company to anybody.

    2017 Jeep Grand Cherokee

    I’ve used several of these and they always work great.
    etrailer videos are a great help!

    2015 Jeep Wrangler

    Lori was spot on in making sure I got the correct base plate assembly and light package for my 2015 Jeep Wrangler Sport. Deliver was within the projected timeframe and installation when as per detailed instructions . Good job Team ETrailer, that is why I keep coming back


    Great tow plate , easy to install


    Fits and works just as it should.


    The install was more challenging than the tow bar itself but we got it done. Be patient with the tail light diodes they are tricky to fit but not impossible. I ended up using some 3m double sided adhesive sticky’s to hold the diodes in place while i pushed the tail light assembly back into position.


    Installation instructions were great, no issues or questions. I ran the wire thru the frame, and used split wire loom and tape to protect wiring when outside the tube frame.

    2019 Chevrolet Blazer

    Product is very well built and is hidden within the bumper/grille. Installation wasn't too difficult, reinstallation of front bumper requires 2 people.
    Pleased with end results.

    2001 Jeep Cherokee

    This is the third time I have order base plates and electrical hook ups from etrailer and love this company. We have a 1979 MCI Bus conversion and it is difficult at time finding things for towing etc for it because of age. Not with etrailer, they have it all. We have towed a 96 S-19 chevy, a 98 Jeep was next and this year we got a 2001 Jeep Cherokee which we got the electrical kit for from and the base plates are still on the way. Everything fits nicely and if you are unsure of how it all goes together just watch their video''s on the etrailer website which are very informational.
    Thank You for being there when we need you. See you all down the road....



    Still working very well and didnt even have to pull the bumper off to install it. very strong units. the electrical hookups worked well also and easy to hookup as well. Lights all work well. The brake cable system I had on my previous Jeep I mover to the cherokee but was a real pain to find a good pass through because of all the mechanicals in the Jeep cherokee but good it through finally.


    This was my choice for my flat tow set up on a 2018 Jeep GC. I did this install myself. it was not difficult.



    One year in and the wiring set up has worked as planned. no issues.


    We tow a 2022 Ford Escape behind our Winnebago motorhome. This wiring kit did the job for us. Everything working great!

    Toyota Land Cruiser

    I used this on a 1988 Toyota Land Cruiser, so I could flat tow it behind an Motorhome. Easy to install!


    Straightforward install on my Jeep Gladiator and no issues.


    Easy install


    The stuff not here

    Show More Reviews

    See what our Experts say about this Roadmaster Tow Bar Wiring

    • Does Roadmaster Universal Hy-Power Diode Wiring Kit Work With LED Lights
      Yes, the LED lights on your truck will not affect the Roadmaster Universal Hy-Power Diode Wiring Kit # RM-154. You will be able to use this kit with those lights and it will work well. I have added a link to a video review below for you to take a look at also.
      view full answer...
    • Can Tow Bar Wiring For 2013 Jeep Wrangler Be Used On 2015 Jeep Cherokee Trailhawk
      If you are planning on flat-towing, both the 2015 Jeep Cherokee Trailhawk and the 2013 Jeep Wrangler can use the same tow bar wiring harness, part # RM-154. This harness will work with 2-wire and 3-wire lighting systems. All of the needed equipment is included with this kit. This will plug directly into the 4-way connector on your camper. I have attached a link to an installation of this kit on a 2014 Cherokee, which should be very similar. I have also attached some helpful articles...
      view full answer...
    • Which Lights Do You Splice Into For Diode Wiring On A Jeep Grand Wagoneer
      The Roadmaster Universal Hy-Power Diode Wiring Kit # RM-154 would splice into the tail lights on the corner of the body and not the lights on the hatch. I've attached a short video below that Jake recently made that will walk you through how to install this kit step by step.
      view full answer...
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    • How to Determine the Wiring Functions of a Vehicle to Install Diode Tow Bar Wiring Kit
      To install a diode tow bar wiring kit like the part # RM-154 you will have to use a circuit tester to test the wires that run to the vehicle taillights and then attach the diode wiring by function to them. I attached an install video that shows the process on a somewhat similar Honda for you to check out and get the idea how it's done.
      view full answer...
    • Wire Colors On Roadmaster Universal Hy-Power Diode Wiring Kit
      On the Roadmaster Universal Hy-Power Diode Wiring Kit # RM-154 referenced in your question, the wire colors are as follows: White is for ground. Brown is for tail lights. Yellow is for left brake and turn. Green is for right brake and turn. I have attached an installation video that you can use for reference.
      view full answer...
    • Parts Needed to Wire Lights on a 1999 Chevy Tracker for Towing Behind a Motorhome
      You can use a kit, like RoadMaster Part # RM-154, to wire your 1999 Chevy Tracker. With an amber turn signal vehicle, you can skip those bulbs and use the brake bulbs for both brake and turn functions. Essentially you ignore that the amber turn signals are there and wire the vehicle like you would a trailer. The amber turn signals will still function when you drive the Tracker, but not when it is towed. The second wiring diagram on the RM-154 page shows how you would wire your set up. I...
      view full answer...
    • Wiring a 1994 Toyota Pickup to Tow Behind a Motorhome
      We carry wiring kits for towing vehicles behind motorhomes. I would recommend RoadMaster part # RM-154. It is a complete kit that will let you wire your 1994 Toyota Pickup to be towed behind your motorhome without using the magnetic tow lights. Since your Toyota should have separate brake and turn signals, you will need one of two wiring diagrams based on whether or not your motorhome has seperate turn signals. Thumbnails of these diagrams can be seen towards the bottom of the product page...
      view full answer...
    • Tow Bar Wiring Running Light Not Working
      It's possible a diode could be bad with the # RM-154 but a more likely scenario is a weak ground. Even if the ground connection is tight, if there is dirt or paint and it is not fully on bare metal, funky things can happen so I would check that.
      view full answer...
    • Does License Plate of Tow Vehicle Need Lit Up When Flat Towing
      It is true that the tow bar lighting kits like the part # RM-154 do not illuminate the license plate of the tow vehicle and it's not really an issue. Reason being is that the plate of the vehicle that's actually driving would still be illuminated (the tow vehicle). The reason you don't need to have the towed vehicle plate illuminated as it's not a vehicle that's doing the driving so being able to identify that vehicle is not relevant since it's not making choices on the highway like the...
      view full answer...
    • How to Wire a 2015 Ford Edge SEL to be Dinghy Towed
      Dinghy wiring the 2015 Ford Edge SEL model is quite a bit different than normal diode wiring because Ford combined the stop, turn and taillight signal on the same wire that goes to the rear facing LEDs in the taillight. To make the # RM-154 kit diodes work properly you will need 2 resistors rated for 50 ohms and 10 watts for LED tail lights or 2 rated for 5 ohms and 10 watts for incandescent tail lights, available from a local electronics supply store. You will also need to wire the diodes...
      view full answer...
      Image 1 for
    • Wiring a 1994 Jeep YJ for Towing Behind a Motorhome
      The T-One harness you were looking at is to tow a trailer behind the Jeep. It will not work in reverse to tow the Jeep behind a motorhome. You will need RoadMaster part # RM-154. There are wiring diagrams on the page to show you how to wire it depending on the taillight configuration of your motorhome.
      view full answer...
    • Wiring Guide for Roadmaster Universal Hy-Power Diode Wiring Kit # RM-154
      Based on my research both your 2002 Bounder motorhome and your 2000 Dodge Durango have combined brake/turn lights. So in this case you will wire the Roadmaster Universal Hy-Power Diode Wiring Kit # RM-154 as shown in the linked wiring diagram.
      view full answer...
      Image 1 for
    • Running Light Function of 2004 Chevy Trailblazer When Flat Towed Using Roadmaster # RM-154
      The Roadmaster Universal Hy-Power Diode Wiring Kit # RM-154 is designed to allow your 2002 Dutch Star Motorhome to power all the lighting of your 2004 Chevy Trailblazer when being flat towed. You should not have the running lights of your Trailblazer turned on independently of the running lights of your motorhome when connected. That could cause the diode to fail but the kit is rated for a max voltage of 24V and max amperage of 85 amps, so it may function even under those conditions.
      view full answer...
    • Options for Installing Diode Style Tow Bar Lighting on 2005 Volkswagen New Beetle
      The easiest way to use diode tow bar wiring on a vehicle that has separate turn signals from stoplights is to wire the vehicle up like it's combined. This will operate the stoplights of the vehicle as if they are combined which will work well. You can still wire up the system to use separate turn signals but you need a total of 6 diodes and a converter box. If you check out the link I attached to this page under the "helpful information" heading you'll see the best ways to wire in diode...
      view full answer...
      Image 1 for
    • Tow Bar Lighting Recommendation for a 2015 Ford Edge Titanium
      I checked with Roadmaster and they list the Diode kit part # RM-154 as a fit for your 2015 Ford Edge Titanium so it would fit and work well for you. I attached an install video that shows this tow bar lighting kit being installed on a 2015 Ford Edge for you to check out as well.
      view full answer...
    • How to Determine If My RV Has Separate or Combined Lighting for Installation of Roadmaster Diodes
      I do believe you're asking how to determine whether or not your RV has a combined or separate lighting system. If the motorhome’s trailer plug energizes the same pins on the 4 way connector for both brake lights and turn signals, then a 3-to-2 converter is already installed and the motorhome should be treated as combined lighting when installing the Roadmaster # RM-154.
      view full answer...
      Image 1 for
    • Will the 4-Way Mounting Bracket # 18144 Secure the 4-Way of the # RM-154
      The 4-way mounting bracket # 18144 will be a little bit big for the 4-way of the RM-154, but I can assure it will secure the 4-way once you press the cap onto the 4-way. Either the cap will keep it in place or the fact that it is plugged into your tow vehicle will keep the 4-way in the bracket. If the hole underneath the light assembly is not large enough to fit the wires of the # RM-154 through you can either look for a different access point or enlarge that hole with a drill or dremel.
      view full answer...
    • Tow Bar Lighting Recommendation for 2015 Titanium Ford Edge
      I checked with Roadmaster and the diode kit part # RM-154 has been confirmed as a fit for your 2015 Ford Edge without any LED light exclusions so I would recommend it for you. I attached an install video link that shows this light kit being installed in a 2015 Ford Edge just like yours.
      view full answer...
    • Troubleshooting No Left Turn Signal or Running Lights on 2014 Jeep Grand Cherokee With RM-154
      If everything works but the running lights and turn signal after you installed the Roadmaster Universal Hy-Power Diode Wiring Kit # RM-154 it sounds like you may just have a weak ground; this is often the cause of these types of issues so you'll want to make sure your grounds are securely attached to bare metal surfaces free of any paint, dirt or corrosion of any kind. Also check your wiring thoroughly to ensure there are none that are crimped, broken or otherwise damaged and your connections...
      view full answer...
    • Will 2009 Chevrolet Silverado 1500 Use Same Tow Bar Wiring # RM-154 Shown in Video for 2013 Model
      Yes, the 2009 Chevrolet Silverado can also use the Roadmaster Universal Hy-Power Diode Wiring Kit, # RM-154, that was featured in our install video with the 2013 truck. I have attached a link to the video for you. Installation will be the same.
      view full answer...
    • What is the Correct Wiring Diagram to Use for a 2017 Ram 1500 When Installing the Hy-Power Diode Kit
      Your 2017 Ram 1500 Longhorn with factory LED taillights has a combined system. The correct diagram when installing the Roadmaster Universal Hy-Power Diode Wiring Kit # RM-154 will depend on what your RV/Motorhome has. Since your Ram 1500 has combined wiring, I have included each diagram that could be correct. 1 for if your RV/Motorhome has combined wiring and 1 if your RV/Motorhome has separate wiring.
      view full answer...
      Image 1 for Image 2 for
    • Dim Tail Lights on 2007 Toyota Yaris Hatchback When Flat-Towed Using Roadmaster Diode Kit # RM-154
      Thank you for providing a detailed description of your lighting issue and of the troubleshooting steps you have taken so far. Diodes should not cause a voltage drop if they are operating properly. You can test whether the diodes are the problem by apply a voltmeter to the upstream and downstream wiring with the MH engine running. If you detect close to 13 volts going into the diodes but substantially less on the output side then the diodes may be defective. There could also potentially...
      view full answer...
    • Can Roadmaster Tow Bar Diode Wiring Kit # RM-154 Install on 2021 Chevy Colorado
      Yes you can use the Roadmaster Tow Bar Wiring kit part # RM-154 on your 2021 Chevy Colorado. I attached an install video for this on a similar 2020 Chevy Colorado for you to check out as well. This kit does not require the vehicle battery to be disconnected so it would not interfere with that in any way.
      view full answer...
    • Tow Bar Diode Wiring Kit Recommendation for a 2015 GMC Acadia
      I checked with Roadmaster and they have confirmed that the Diode Kit part # RM-154 that you referenced is a fit for your GMC Acadia. Based on the way you described the wiring of your vehicle it sounds like you have a combined tail light setup. Meaning your brake lights and blinkers are on the same bulb. You would want to follow the chart I attached as well as the FAQ article I attached on how this would wire it.
      view full answer...
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