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RoadMaster Stop Light Switch Kit
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Roadmaster

RoadMaster Stop Light Switch Kit

Part Number: RM89ZR
In Stock
$47.85
Retail:$64.09
You Save: 25%
Flat Tow Brake System
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etrailer Installation
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Avoid damage to your vehicle by ensuring that your supplemental braking system is properly positioned and working effectively. Kit activates your RV monitoring system to alert you when the brakes of your towed car are being applied. 1-800-940-8924 to order Roadmaster flat tow brake system part number RM89ZR or order online at etrailer.com. Free expert support on all Roadmaster products. Great prices and Fastest Shipping for RoadMaster Stop Light Switch Kit. Flat Tow Brake System reviews from real customers.
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  • Reviews (702)
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Roadmaster Flat Tow Brake System - RM89ZR

Highlights

  • Know When Your Toad’s Brakes Engage: Triggers your RV’s monitor when the car’s pedal is pressed so you can confirm the braking system is working.
  • Prevents Costly Brake Damage: Lets you catch improper setup that could hold the pedal down and wear out tires or brakes.
  • Works Where No “Tow” Ignition Mode Exists: Keeps your brake signal active even when the key can’t be left in a tow position.
  • Reliable Power Connection: Wires directly into the fuse box for a steady 12-volt current and consistent signal.
  • Custom-Fit Design: Tailored installation ensures proper pedal sensing and dependable monitoring.
Made in USA

Features to know about

Know Exactly When Your Brakes Engage: Direct Pedal Activation

When you’re towing, you want to be sure your supplemental braking system is doing its job. This stop light switch kit activates your motorhome’s brake-monitoring system whenever the towed car’s brake pedal is actually pressed. Instead of guessing based on air cylinder movement, you get confirmation of what’s really happening at the pedal. That means you’ll always know when your brakes are applied and can avoid issues like a system pressing the pedal continuously.

Protect Your Vehicle from Brake Damage: Constant Current Connection

Improper brake feedback can lead to serious wear or tire drag. The RoadMaster Stop Light Switch Kit wires directly into the towed car’s fuse box for a constant 12-volt current, ensuring accurate signals and steady operation. With the switch confirming pedal movement, you can catch improper setup before it causes damage to your tires or braking system.

Reliable Monitoring When There’s No “Tow” Position: Always-On Functionality

Some vehicles don’t offer a tow position in the ignition, which can interfere with normal brake signal operation. This kit solves that by providing an independent connection that keeps your monitoring system active whether the ignition is on or off. It ensures that your supplemental braking system still triggers the alert in your RV every time the pedal moves, keeping you informed through every trip.

Durable Construction That Stays in Place

The bracket and switch are built for a secure, permanent fit once adjusted. Reviewers note the sturdy feel of the bracket and the solid contact it provides with the brake pedal arm. Once mounted and wired in, the system delivers consistent readings so you can tow with confidence knowing your brake signals are accurate and reliable.

Specs

Electrical

  • Voltage: 12 Volts

Application

  • Application: custom fit for your vehicle

What You Need to Flat Tow

Flat towing can be a much more convenient way to take your car RVing with you than using a trailer or a tow dolly. It'll save you storage space both at home and at the campsite, and it takes less time and hassle to hook up.


To flat tow your vehicle, there are 5 basic components you're going to need: a tow bar, a base plate kit, a safety cable set, tow bar wiring, and a flat tow braking system.


For the RV Between the RV and Towed Car For the Towed Car
Hitch Tow bar Base plate
Wiring plug Safety cables Braking system
Wiring adapter cord Wiring kit/diodes

The custom-fit base plate installs on the frame of your toad so you can connect the car to your RV with a tow bar. Hook up safety cables between the vehicles to ensure that the toad does not separate from the motorhome if the tow bar becomes detached. Tow bar wiring syncs your vehicle's signal lights with your motorhome's tail lights, as required by law in most states. Finally, the flat tow braking system - also required in most states - activates the brakes in the toad when you hit the brakes in the RV, making for smoother, safer braking, and preventing wear on your motorhome.

751506 Road Master Stop Light Switch Kit



This Product Fits The Following Vehicles




Customer Satisfaction Score:

Ratings & Reviews

4.7

702 reviews
Review sort icon
Avoid damage to your vehicle by ensuring that your supplemental braking system is properly positioned and working effectively. Kit activates your RV monitoring system to alert you when the brakes of your towed car are being applied.

by:

etrailer’s installation video was very helpful. However, the mounting bracket holes on either end seem to be the same size (the video and instructions state that the switch fits into only one end but for me it fit into both). Consequently, it is not clear which side of the bracket to use for the switch vs the vehicle stud. One other installation hint, perhaps unique to the Wrangler Rubicon or Wranglers with upgraded audio/Uconnect, there is an electronic module (3”x4”), mounted to the dash framework behind the lower dash panel, that must be dismounted in order to allow access to the bracket mounting location (see photo).



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Installed on a 2023 Equinox LT (AWD). I believe there may have been a change to the Equinox brake pedal assembly from prior years. Because of this, I was not able to get the switch located properly with the bracket that is included in the kit. I fashioned my own mounting plate from a piece of diamondplate which I bolted to the brake lever bracketry. This works great and is rock solid.



by:

Easy installation. I had an issue getting the kit ordered, but the customer service agent was phenomenal in her assistance getting it resolved.



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It works as designed. Tricky for this old fat guy to work under the jeep dash but eventually got it installed and adjusted.



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Was disappointed that your site said this was the part I needed so I ordered it. Then realized it was not correct part. Called next day to cancel and Oder correct part. I was told I could not cancel it and would have to pay to ship it back. The correct part which was ordered second came 2 days before first part. To get a refund I still had to pay to ship it back. Other than this trailer has been good to work with and quality parts.



by:

Thank you, order arrived as promised, and install was easy and fit my 2025 Jeep Grand Cherokee Overland perfect to operate my brake light on my Motorhome dash.



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Easy installation. Fit perfectly in my 2014 Grand Cherokee.



by:

Works great fairly easy install. It has been in use for the last 8 month's with no issues. Here may be some helpful hints that I found when installing. Use 10-12" long extension for 13mm nut (left side of opening panel that was removed). Install bracket. Adjust plunger & backing nut by feel. Remove bracket. Install switch with ring washer & nut. Crimp red & green wires on switch wires. Reinstall bracket under dash.



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Ill give it 3 stars because I had to shim the bracket to make the plunger line up with the brake arm. But it works well so far.



by:

It is my opinion that the universal brake light switch is the easy way to go. Hardest part doing the DIY way is the place you are working in. I.have a few sore spots trying to get underneath the steering wheel. The benefit is you have instant info that the switch works. A light comes on when you push the break pedal



by:

Roadmaster products are great, very pleased with the superb instructions. Very difficult to mount the pulley for the invisibrake in my Ford Maverick. Trying to drill stainless steel behind the brake pedal was near impossible. Could a bracket for the pulley be mounted on the same studs as the Stop Light Switch?



by:

I have a ‘23 Bronco with the Lux package. The Bronco had a factory brake switch in the spot this thing would go. Advice was unclear whether I could use a factory wire to install my brake controller. I went with the wire that lit the test light when brakes were pressed (key on). I think it was violet with a stripe at the plug for a factory Brake controller. I don’t have the factory tow package. Seems to work but not yet tested with a trailer. Only 3 stars because of the uncertainty. I’ll use this switch on a different project.



by:

Product works great...But was shorted the female connector to terminal 1...Cost over 5 dollars at Auto Zone.As no one sells just one.....Its in the picture...Not in my parts bag...But a perfect fit on the brake switch mount .Three stars only because I had to go buy a connector to complete the job.



by:

One year later and I haven't had to touch this system even once. It just works, all the time, every time. Very happy with this kit. Works perfectly in my 2019 Toad (Jeep Cherokee).



by:

I couldn’t use the towed vehicle’s brake light circuit on the last two pickups I’ve set up. On the truck before this I robbed a little refrigerator switch that turns on the light when you open the door and rigged up my own. Alas, that wouldn’t work on this newest GMC Canyon. Then I found this device. Wow, what a quick and easy installation. It works perfectly.

I do have a suggestion for ETrailer. Show the actual switch dimensions in your listing. Though the actual switch is quite small, I was worried I wouldn’t be able to make it fit. With nothing but pictures and nothing for scale, it was a concern.



by:

I installed the item in my 2024 Bronco to support braking indication in the motorhome while being towed, since Ford does not include one these days. As far as I can tell, this is the only commercially available kit to avoid cobbling up your own design. It is tedious to install mechanically and, especially tedious to adjust transverse mount position and depth of travel. The button on the switch is too small, requiring very precise alignment to the brake pedal arm (approx 1/4" wide) in the transverse direction from the switch movement. There is no screw type adjustment in that direction so bracket bending/and or bracket mounting spacers is required. I am also afraid the switch button being small and made of some type of poly, it will slip sideways, deform, or wear with even the slightest offset and begin to push the bracket aside. However, it has worked in a few thousand miles of towing behind a motorhome so far. I will keep an eye on this and test function whenever hooking up to tow (a normal practice anyway). I kept thinking it would be easier to use a long lever low force microswitch instead of a tiny soft-tipped, rather hard spring or drag, pushbutton, which would require its own mounting design. Maybe a small highly adjustable ball clamp mount work with a microswitch as well. But I must resist my engineering background tendencies in exchange for getting the job done! Sorry for the quality of the photos. It is in a difficult place for phone camera.



by:

Thanks everyone at etrailer for your help and quick response and shipping! My project turned out really great as you can see in the pictures I have included. The plug for the removable holders I 3D printed. Thanks Fred



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Installed on 2023 F150
Bracket looks
well made
It is about 1/2" to long for the switch to make contact with brake peddle arm
Took a lot of bending of the bracket to get it to work



by:

Works as advertised


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See what our Experts say about this Roadmaster Flat Tow Brake System

  • Complete Flat Towing Setup for a 2024 Ford F-150 Raptor
    Daren, for your 2024 Ford F-150 Raptor you are going to need: - A base plate kit, like the etrailer Invisible Base Plate Kit # e86YR, - A set of tow bars, like the etrailer XHD Non-Binding Tow Bar # e94ZR, - A braking system, like the Roadmaster BrakeMaster w/ Pressure Reducer for RVs w Air or Air-Over-Hydraulic Brake # RM-9160-900002, using the RoadMaster Stop Light Switch Kit # RM89ZR and the Roadmaster BrakeMaster Custom Fit Seat Adapter # RM-88316, & - A wiring harness, like the...
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  • Complete Flat Tow Set Up For 2024 Ford F150 4x4 Hybrid
    Hello Vance. Wow, that is a nice truck to pull behind your motorhome! Here are all the parts I recommend for flat towing your 2024 Ford F150 4x4 Hybrid: -Base Plate Kit: Demco Tabless Base Plate Kit - Removable Arms # DM56MV -Tow Bars: Demco Dominator Non-Binding Tow Bar - RV Mount - 2" Hitch - 7,500 lbs # DM9511008 -Wiring Kit: For LED tail lights- Roadmaster Smart Diode 7-Wire to 6-Wire Wiring Kit for Variable Voltage LED Tail Lights # RM38FR. For Incandescent tail lights- Roadmaster...
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  • Availability of Hopkins Brake Light Relay for 2025 Ford F-150
    Hey Jay! Hopkins is for sale right now since they're part of First Brands which went bankrupt. We don't actually know when the Hopkins Custom Tail Light Wiring Kit # HM77VR will be back, and we don't have that relay either. Even if we did have it, I highly recommend using the Roadmaster 4-Diode Universal Wiring Kit for Towed Vehicles # RM-15267 instead. Roadmaster has the most reliable wiring which is exactly what you want when you're flat towing. You will also want a 6-way, which this...
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  • Trouble Finding Brake Light Wire on a 2025 Ford F-150
    Hey Dennis, thanks for reaching out! According to the Roadmaster fitguide you're going to need a brake light switch as well since they weren't able to locate the color of the OEM brake light circuit wire. You'll use part # RM42MR if you have an adjustable brake pedal, or part # RM89ZR if you don't have an adjustable brake pedal. Once the brake light switch kit is in place, you'll have the signal you need to install the Brake-Lite Relay Kit # RM-88400. Are you installing all of your flat...
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  • Location of Cold Side of Stop Light Switch for Brake Controller Installation on 2022 Ford F-150
    It looks like the OEM brake light switch is unusable on the 2022 Ford F-150. To complete the installation you will need to add the RoadMaster Stop Light Switch Kit # RM89ZR if you do NOT have an adjustable brake pedal or # RM42MR if you DO have an adjustable brake pedal. The red wire on your # RED52VR will connect to this to complete the installation.
    view full answer...
  • Recommended Flat Towing Wiring Harness for a 2024 Ford F-150
    What a great question Howard. You should direct that request to Curt, Blue Ox, or Demco though. We don't make the wiring harnesses like the Curt item # C75WR you purchased, which does not have diodes in it. No one makes a plug and play for a 6-Way flat towing connection. The diodes included in the Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights item # RM38FR, or item # RM-152-1676-7 if you don't have LED lights, are installed to prevent feedback between a RV's electrical...
    view full answer...
  • Correct Roadmaster BrakeMaster Seat Adapter for a 2024 Ford F-150
    Hey Steve! The correct seat adapter for your 2024 Ford F-150 is the Roadmaster item # RM-88316, you were looking at. This is designed for the Roadmaster BrakeMaster item # RM-9160-900002 and item # RM-9060-900002. You're also going to need a stop light switch. There's two options depending on what brake pedals you have. I have listed them below: Adjustable Pedals - Roadmaster Stop Light Switch Kit item # RM42MR Non-Adjustable Pedals - RoadMaster Stop Light Switch Kit item # RM89ZR
    view full answer...
  • Location of Brake Light Switch on 2023 Ford F-150 Installing Roadmaster InvisiBrake
    Hey Paul! The OEM switch on your 2023 F-150 is unusable. You will need to add a RoadMaster Stop Light Switch Kit to complete the installation of your InvisiBrake # RM-8700. You can choose from the following based on your configuration: -Non-Hybrid Model With Non-Adjustable Brake Pedals use # RM89ZR -Non-Hybrid Model With Adjustable Brake Pedals use # RM42MR -Hybrid Model use # RM-751000 What motorhome are you towing with and where are you headed once you get your F-150 set up?
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  • Steps To Find Cold Side Brake Light Switch Wire On 2023 Ford F-150 When Installing Brake Controller
    We haven't had a chance to install a brake controller in a 2023 Ford F-150 yet (3/27/2023), so I can't tell you the wire color but I can tell you how to figure out which one you need to hook to. You'll need to use a circuit tester like # PTW2993 and with the truck on but not running, press the brake pedal and test the wires going to the brake switch (this will be a plastic looking thing on the brake pedal arm). You're looking for one that only has power when the pedal is pressed. If you...
    view full answer...
  • 2019 Ford F-150 Flat Tow Parts Recommendation with Blue Ox Avail Tow Bar
    I'm happy to help you get your 2019 Ford F-150 ready to flat tow! The Stay-IN-Play DUO braking system is another excellent choice and by going that route you won't need the Stop Light Switch Kit # RM89ZR but you will still need the Relay Kit # RM-88400 to keep the brake light signal on your F-150 from overriding the turn signal from the RV when you're applying the brakes during a turn. With the parts listed out here is the bare minimum that you need: etrailer Invisible Base Plate Kit -...
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  • Can I Flat Tow a 2019 Ford F-150 With My Motorhome
    People flat tow pickups all the time and from what I could find it looks like your 2020 Thor Challenger 37TB can tow up to 8,000 lbs (you'll want to verify this in your owner's manual) which is more than enough for towing your 2019 Ford F-150. As far as recommendations go, I really like the Roadmaster products because they put a lot of thought into their designs so the only thing non-Roadmaster that I'll have is the tow bar simply because it's hard to argue with the price-point of our...
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  • Availability of Light to Know when Flat Towed Vehicle Brakes are Applied
    Hey Keith, we have the Roadmaster Universal Braking Monitor part # RM-9530 which will give you exactly what you are looking for.
    view full answer...
  • 2019 Ford F-150 etrailer and Blue Ox Base Plate Kit Recommendation for Blue Ox Tow Bar
    Yes, the etrailer Base Plate Kit # e86YR is compatible with the Blue Ox Avail Tow Bar # BX7420 but you will need the Adapter Kit # DM9523127. I recommend using the etrailer Base Plate Kit # e86YR over the Blue Ox Base Plate Kit # BO74FR for your 2019 Ford F-150. The base plate kits are virtually the same when it comes to quality so since you like the looks and price point of the etrailer kit better that's what you should go with. You will also need some additional parts for flat towing...
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Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Jeff D
Installed by:
Jeff D
Employee Ryan G
Installed by:
Ryan G
Employee Jameson C
Expert Research:
Jameson C
Employee Joshua S
Video Edited:
Joshua S
Employee Wilson B
Updated by:
Wilson B
Employee Mike S
Written by:
Mike S

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