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  1. Flat Tow Wiring Harness
  2. Roadmaster
  3. Diode Kit
  4. Splices into Vehicle Wiring
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THIS ITEM IS NOT A FIT FOR
2005 Dodge Magnum
Roadmaster

Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights

Part Number: RM47ZR
$143.89
Retail:$151.54
You Save: $7.65
Flat Tow Wiring Harness
Not Confirmed to Fit

2005 Dodge Magnum

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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 kit is for variable voltage/multiplex LED tail lights. 1-800-940-8924 to order Roadmaster flat tow wiring harness part number RM47ZR 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. Flat Tow Wiring Harness reviews from real customers.
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Roadmaster Flat Tow Wiring Harness - RM47ZR

  • Diode Kit
  • Splices into Vehicle Wiring
  • 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 kit is for variable voltage/multiplex LED tail lights.


Features:

  • Displays RV's brake and turn signals correctly 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
  • Includes:
    • 2 Smart diodes
    • Wiring harness, split loom, ring terminals, and zip ties
  • Made in the USA


Specs:

  • Application: variable voltage tail lights with LEDs only
  • Maximum amperage: 5 amps
  • Maximum voltage: 16 volts
  • Wiring harness length: 27'
  • 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.)

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 RO94FR (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.



Additional Components

To complete your flat tow setup, you will need either a 4-way or 6-way round electrical connector on the front of your vehicle and a power cable to plug into the RV. Pick up a Roadmaster kit (RM-164-7 or RM-146-7 - sold separately) if you're still missing these important components.


Wiring Diagram for Roadmaster Smart Diode Kit

Smart Diode Wiring Diagram


152789 Road Master Wiring Kit with Smart Diodes for Variable Volt and LED Bulbs

Installation Details RM47ZR Installation instructionsAlternate Instructions RM47ZR Installation instructions

This Product Fits The Following Vehicles



California residents: click here


Customer Satisfaction Score:

Ratings & Reviews

4.7

326 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 kit is for variable voltage/multiplex LED tail lights.

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

  • List of Everything Needed to Flat Tow 2023 Jeep Wrangler
    Hi Tony, thanks for writing in and yes, we can 100% get your 2023 Jeep Wrangler set up to be flat towed behind your Holiday Rambler motorhome. To make it easy to order I'll go ahead and list everything out for you. - Base Plate Kit: Roadmaster Direct-Connect Base Plate Kit # RM-521453-5 - Tow Bar: Roadmaster Nighthawk All Terrain, Non-Binding Tow Bar # RM-676 - Wiring Kit: Roadmaster Universal Hy-Power Diode Wiring Kit # RM-152 OR Wiring Kit with Smart Diodes # RM47ZR (See below explanation...
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  • Recommended Complete Flat Towing Setup for a 2024 Jeep Wrangler
    Hey Christian, welcome to the world of RV-ing! So in addition to the Roadmaster Nighthawk # RM-676 you're also goin to need: - A baseplate kit, like the Roadmaster Direct-Connect Base Plate Kit # RM-521453-5. These attach to the Jeep itself so you can hook up the tow bars. - A braking system, like the Demco Stay-IN-Play Duo Flat Tow Brake System for RVs w/ Hydraulic Brakes # SM99251 with the stop light switch # RM-751490. This braking system is a bit more involved set-up wise, but once...
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  • Recommended Plug and Play Flat Tow Wiring Harness for a 2024 Jeep Wrangler Sport
    Hey James, welcome back! The only plug and play wiring harness I have for flat towing is the Curt Custom Tail Light Wiring Kit for Towed Vehicles item # C96JR. This has a 4-way connector that plugs into your motorhome. This plug and play harness connects directly to your 2024 Jeep Wrangler Sport behind the driver's-side and passenger's-side tail lights. Please note that if you have a 4-way trailer connector like item # 56407 you won't be able to use it will you're flat towing your Jeep....
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  • Flat Tow Parts for a 2025 Jeep Grand Cherokee Overland
    Hey Eddie, thanks for reaching out! It looks like you were already able to get the following parts in an order: - Roadmaster Direct-Connect Base Plate Kit # RM77ZR - Roadmaster Nighthawk All-Terrain # RM-676 - Smart Diode Kit # RM47ZR - Tow Bar Cover # RM-055-3 - Battery Charge Line Kit # RM-156-25 - Tow Defender # RM-4750 - Demco Air Force One # DM23MV I really like all of the parts that you ordered, and from what I'm seeing you aren't missing anything! Let me know if you end...
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  • Will the Curt Custom Tail Light Wiring Kit C96JR Work w/ LEDs on a 2025 Wrangler Unlimited?
    Hey Jim. The Curt Custom Tail Light Wiring Kit for Towed Vehicles item # C96JR is indeed compatible with the LED lights on your 2025 Jeep Wrangler Unlimited. It plugs into your factory wiring harness behind the tail lights. The only issue would be if your Jeep has the ParkSense proximity sensors. If your Jeep has the ParkSense feature you'll need the Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights item # RM47ZR. It looks like you've purchased a few flat tow accessories...
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  • Can Tow Bar Wiring and Trailer Wiring Install at Same Time On 2025 Jeep Wrangler
    Hey Lee, that's a great question but it doesn't matter where the lighting kit part # RM47ZR wires in relation to the trailer wiring. As long as both are installed on the right circuits everything will work great together. Do you think you'll ever attempt to tow the Wrangler while it's towing a trailer?
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  • Recommended Parts Needed for Flat Towing a 2023 Jeep Gladiator Mojave
    For a complete flat towing setup on your 2023 Jeep Gladiator Mojave you will need a base plate kit, tow bar, safety cables, vehicle tow bar wiring, a supplemental braking system, and possibly a high-low adapter. Here are the parts I recommend for you: Base Plate Kit - # RM77VR Tow Bar - # RM-676 (comes with safety cables) Wiring - # RM-154 (standard) OR # RM47ZR (if you have ParkSense feature) Brake System - # DM86VR for motorhome hydraulic brakes OR # DM26VR for motorhome air brakes High-Low...
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  • Will Roadmaster Falcon Tow 2025 Jeep Grand Cherokee Overland
    Hi John; as long as you aren't exceeding that 6,000 lb capacity it won't be a problem so you can use the Falcon to tow your 2025 Jeep Grand Cherokee Overland. Since the Overland has tow hooks the correct Roadmaster Direct-Connect Base Plate Kit is the # RM77ZR. Since you want to use the Blue Ox Patriot # BLU37TR you will also need the 12 Volt Outlet Kit, 20 amps # RM-9332. If you need new wiring the Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights # RM63MR is the best option...
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  • Recommended Wiring for a 2023 Jeep Wrangler Unlimited Sport w/ Park Sense
    Thanks for all of the information Brent! You have done your home work extremely well. Let me reassure you that as long as your Newmar Dutch Star has a fully functional 7-way connector you won't need to address anything on your RV as far as wiring goes. We'll handle that with parts for the Jeep. The fact you were able to successfully tow a 2015 Jeep without any issues means the 4-way and 7-way are already combining the signals leaving the item # RM-732 as a redundant part you won't need....
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  • Recommended Flat Towing Parts for a 2022 Jeep Wrangler 4xe w/a Factory Winch Bumper
    You're welcome! Thanks for all of the information! You could go with the Blue Ox item # BX1139 but I've got a different recommendation that will save you some money and get you a better setup. The Curt RVi battery charger is definitely the way to go. To flat tow your 2022 Jeep Wrangler 4xe, I recommend the following parts: Tow Bar and Safety Chains - 8,000 lbs Roadmaster Sterling All-Terrain Tow Bar item # RM-576. This kit includes safety chains, the 7-way to 6-way cable to connect to...
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  • Will Roadmaster Base Plate Kit for 2024 Jeep Wrangler 4XE Require Removal of Skid Plate
    Hi Lisa; the Roadmaster Direct-Connect Base Plate Kit # RM-521453-5 will require trimming your skid plate. You will remove it, trim it as seen in the picture below, and reinstall it when you're finished. There is really no way around this, and the same is true for other base plate kits. I'm assuming you already have part of your wiring from the Nighthawk # RM-676. If you have the ParkSense proximity sensors you need the # RM47ZR and if you do not have ParkSense the # RM-154 to complete...
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  • 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...
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  • Recommended Wiring Harness for a 2021 Jeep Wrangler Unlimited W/ Park Assist
    Michael, since your Jeep has the park assist then you are going to need the Roadmaster Wiring Kit with Smart Diodes for Variable Voltage LED Tail Lights # RM47ZR. This kit is going to ensure that your LED lights function as they should while being towed, will prevent electrical feedback, and includes two smart diodes, a wiring harness, a split loom, ring terminals and zip ties,
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  • Parts Needed to Use 2021 Jeep Wrangler Unlimited Rubicon Lights When Flat Towing
    Hello again Bob; you are correct, you do not need the # RM-88400. Parts like this relay kit are pretty vehicle specific and not part of the flat tow setup for your 2021 Rubicon. What you do need is a wiring kit so your Jeep signal lights work together with your motorhome. If you do not have ParkSense you can use # RM-15267. If you do have ParkSense you need # RM63MR instead. I attached some installation videos below for your reference.
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  • Does Standard Diode Wiring Kit Fit 2023 Jeep Wrangler For Flat Towing
    The correct tow bar wiring diode kit will depend on if your 2023 Jeep Wrangler has the ParkSense proximity sensors or not. If your vehicle does have the ParkSense you will need the kit that has smart diodes so it will ensure that your tail lights get the proper voltage. The reason for that is Jeeps with ParkSense have variable voltage tail lights, which means two different voltages depending on if the signal is for braking or turning. If you do have the ParkSense you will need the Roadmaster...
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  • Recommended Flat Towing Set Up for a 2025 Jeep Wrangler Sport
    Hey Steven! The correct seat adapter for your 2-door Wrangler is the RoadMaster BrakeMaster Custom Seat Adapter item # RM87VR. This works with both the Roadmaster BrakeMaster for RVs w/ Hydraulic Brakes item # RM-9060 and the Air-Over-Hydraulic Brakes item # RM-9160. Here are the rest of the parts you'll need to flat tow your 2025 Jeep Wrangler Sport: Tow Bar and Safety Chains - etrailer SD Non-Binding Tow Bar for Roadmaster Direct-Connect Base Plates item # e74ZR Base Plate Kit - Roadmaster...
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  • Wiring Harness For Flat Towing A 2025 Jeep Wrangler JL
    Hi Greg! We definitely have what you are looking for. You didn't mention if you have a braking system for your 2025 Jeep Wrangler JL or not, so I have both options listed below. With Braking System No LEDs or ParkSense: Roadmaster 4-Diode Universal Wiring Kit for Towed Vehicles - 7-Way to 6-Way Coiled Adapter Cord # RM-15267 With LEDs and/or ParkSense: Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights - 7-Way to 6-Way Adapter Cord # RM63MR Without Braking System No LEDs...
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  • How To Power A Third Brake Light With Diode Wiring While Flat Towing
    The reason the third brake light isn't coming on is because the Roadmaster Wiring Kit with Smart Diodes for Variable Voltage LED Tail Lights # RM47ZR is only being wired to the just the tail lights. To get the third brake light to activate you would need to splice in a jumper wire between the third brake light and the the "RV Brake In" on the diode. You would need an additional Smart Diode # RO54FR for the third brake light and essentially wire it the same as one of your tail lights....
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  • Recommended Supplemental Braking System For A 2021 Jeep Wrangler Rubicon
    The Demco Stay-IN-Play DUO Supplemental Braking System w/ Wireless Coachlink Monitor - Proportional # DM86VR and Brake Buddy Stealth Supplemental Braking System - Proportional # HM39530 are very similar systems with only a few differences. The first one being the cost, the # DM86VR has a higher cost than the # HM39530. The # HM39530 comes with a charge line kit which will keep your vehicle's battery charged, whereas the # DM86VR would require you to purchase a charge line kit like the #...
    view full answer...
  • Which Vehicle Taillight Wire Runs to Roadmaster Smart Diode Kit on 2024 Jeep Wrangler Unlimited
    Hello Mike; when installing the # RM47ZR you need to use the taillight wire. I'm assuming you have ParkSense since you got the smart diode kit. If you use the green or yellow brake light wire it will mess with the system on Jeeps that have ParkSense.
    view full answer...
  • What Flat Tow Wiring do I Need for My 2021 Jeep Grand Cherokee with Parksense?
    Hello Roy, I was working with Roadmaster on this after your first question, and I just heard back from them. They mentioned they are not aware of any 2021 Jeep Grand Cherokee models equipped with ParkSense. I am not saying you don’t have it, but I would definitely double check just to be sure. If you do have ParkSense, you will need the Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights # RM47ZR. If you do not have ParkSense, you will need the Roadmaster Universal Hy-Power...
    view full answer...
  • Parts Needed to Flat Tow 2024 Jeep Wrangler Behind Motorhome
    Hey Doug, we can definitely help with all of the parts you need to flat tow your 2024 Jeep Wrangler. The first thing you'll need is a base plate kit. For that the Blue Ox part # BX1139 that you referenced is correct and a great, easy-to-use option. In addition to the base plates, you will also need a compatible tow bar, safety cables, lighting, and supplemental braking to flat tow your vehicle. One of the most popular compatible tow bars is the Blue Ox Avail # BX7420 which comes with...
    view full answer...
  • Install Videos for Roadmaster Diode Kit and Demco Stay N Play for Jeep Wrangler Unlimited
    Hey Lee, I attached two install videos to this page down below. One for the Roadmaster diode kit part # RM47ZR on a similar Jeep Wrangler Unlimited to yours as well as one for the Demco Stay N Play part # SM99251. These two kits install independent of each other so there isn't a video out there that shows how they would both install at the same time. You can just do one at a time and not worry about how that might affect the install of the other.
    view full answer...
  • Parts Needed To Flat Tow A 2023 Jeep Wrangler Rubicon 392 With A Roadmaster Nighthawk
    Hey Mitch, Aside from your Nighthawk Tow Bar you'll need the following components: Baseplate: Roadmaster Direct-Connect Base Plate Kit # RM-521453-5 Tow Bar Wiring Kit: Since you should already have the 7-way cable and 6-pole socket you should just need the diodes and wiring # RM-152 to transfer your light signals. If you have ParkSense proximity sensors you'll need the # RM47ZR instead. Braking System: If your motorhome has hydraulic brakes then you'll want the Demco Stay-IN-Play...
    view full answer...


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