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FITS 2021 Jeep Grand Cherokee
Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights
Roadmaster

Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights

Part Number: RM47ZR
In Stock
$144.47
Retail:$162.37
You Save: $17.90
Flat Tow Wiring Harness
Confirmed to Fit
2021 Jeep Grand Cherokee

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Call etrailer.com at 1-800-940-8924 for expert service. We are your Jeep flat tow wiring harness experts, and offer a great price. etrailer.com carries a complete line of Roadmaster products for your Jeep Grand Cherokee 2021. Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights part RM47ZR from Roadmaster can be ordered online at etrailer.com. Complete flat tow wiring harness installation instructions and technical support.
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2021 Jeep Grand Cherokee - Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights

  • Diode Kit
  • Splices into Vehicle Wiring
  • Universal
  • Tail Light Mount
  • Roadmaster
  • 27 Foot Long Harness

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

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 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

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  • Recommended Diode Kit for a 2021 Jeep Grand Cherokee Limited
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  • Does Standard Diode Wiring Kit Fit 2023 Jeep Wrangler For Flat Towing
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  • How Can I Add A Charge Line To My 2023 Jeep Cherokee Trailhawk?
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