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When your supplemental braking system presses the pedal, it can cause your brake lights to override your RV’s turn signals—so drivers behind you can’t tell if you’re stopping or turning. The Roadmaster Brake-Lite Relay Kit solves that by keeping the towed vehicle’s brake signal from overriding the RV’s lighting commands. It lets your signal lights flash in sync with your RV, even when the brake pedal is pushed. The kit activates automatically with the RV’s running lights and doesn’t interfere with the vehicle’s electrical system. The result is clear communication on the road and safer towing in every condition.
Whether your towed vehicle uses combined or separate lighting, this relay keeps things working right. It’s required on combined systems when using a supplemental braking setup and also needed for separate systems wired with a 4-diode or TrailerMate harness instead of a 6-diode kit. The relay ensures the correct signal gets through no matter the wiring method, so your lights always match your RV’s actions.
The kit includes the relay, fuse tap, connectors, and ties needed for a standard installation. It doesn’t alter the factory wiring beyond what’s necessary and can be installed in normally open or normally closed configurations depending on the vehicle’s brake circuit. Once in place, it automatically manages the brake and signal balance every time you tow—no switches or manual adjustments required.
Designed by Roadmaster for dependable long-term use, the Brake-Lite Relay Kit carries a limited lifetime warranty and has proven itself in thousands of towing setups. Once installed, it quietly does its job trip after trip, keeping your towed vehicle’s lights performing exactly as they should.
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.
Customer Satisfaction Score:
87% were satisfied with this product
13% of customers were not satisfied
Ratings & Reviews
John
6/10/2025
Checking in after 1 year. No problems to report. Just works!
Keith C.
5/3/2025
It worked great until I sold the vehicle. Used eTrailer to set up my new vehicle
Michael
4/19/2025
After a year and many miles towing all lights and hardware are functioning like the day they were installed. Etrailer, keep supplying quality products and techs providing video installation steps.
Roy
7/30/2018
Still very happy with our purchase. We’ve towed over 10k miles and have had zero issues with our tow setup. I’ve shared my experience with several other RVrs and recommended your company for their needs. Thank you
Jeffrey
11/19/2022
The performance of this tow bar and associated hardware has been outstanding! Service and warranty follow up service from Roadmaster has also been outstanding! I am very satisfied with my purchase.
Robert M.
2/4/2020
The system continues to work as expected. We always perform a light check when hooking up the vehicle and have not had any issues with these components.
John M.
6/15/2018
I am still in love with the products. My only issue is having enough time to use them more.
Rich L.
11/13/2017
Products are working well, have not had any problems with the system
Dennis R.
12/6/2017
Product works great. Towed Ford Flex over 12,000 miles
Joseph D.
7/2/2020
Since working through the installation problems, everything has been great. Although there were installation problems, they were worth it to have a simple hookup when towing.
Drew G.
3/5/2018
Glad I installed it. Nothing to think about when hooking up.
Do you have a question about this Flat Tow Brake System?
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Richard
10/24/2018
Working great with no problems.