How To Tell If My Jeep Needs A Brake Light Relay When Flat Towing
Updated 10/09/2025 | Published 10/07/2025
Products Featured in This Question
Question:
I plan to flat-tow a 2025 Jeep Wrangler, 4-door, Rubicon. Is the RVI44FR braking system compatible with the Curt Custom wiring kit C96JR? I am concerned that the pedal brake light signal from the Jeep would interfere with the RV brake light signal to the rear Jeep lights.
asked by: Jon Y
Expert Reply:
Hey Jon,
This issue does not happen in every vehicle, but in some it does. Basically the vehicle is overriding the motorhomes signals. To fix this issue a brake light relay switch is needed to be installed. The brake system # RVI44FR and the wiring harness # C96JR are compatible and good options to go with. I am going to attach some questions we ask you to answer to determine if your vehicle needs a brake light relay switch. This will determine if your vehicle will do what you described or if it will be fine.
Is a Relay Required?
To determine if a brake light relay is needed to properly wire your vehicle to be towed, answer the following questions.
Are you using a supplemental braking system that depresses the brake pedal in your towed car?
No - You do not need a brake light relay.
Yes - You may need a brake light relay. Continue on to the next question.
Do the brake lights on your towed car illuminate while the engine is off?
No - You do not need a brake light relay.
Yes - You may need a brake light relay. Continue on to the next question.
Do your towed car's brake lights act as both the brake signals and the turn signals?
No - You may need a brake light relay. Continue on to the next question.
Yes - Your towed car has a combined lighting system. You will need a brake light relay to ensure proper activation of its signal lights.
Does your towed car have separate brake lights and turn signals?
No - Your towed car has a combined lighting system. You will need a brake light relay.
Yes - Your towed car has a separate lighting system. You may need a brake light relay. Continue on to the next question.
Are you wiring your vehicle with a six-diode kit or a TowDaddy custom wiring harness?
No - You will need a brake light relay to ensure proper activation of your towed car's signal lights.
Yes - You do not need a brake light relay.
If you do end up needing a brake light relay we have got just that for you. You will need the Roadmaster # RM-88400. Let me know if you have any questions about this. What motorhome are you pulling the Jeep with?
Product Page this Question was Asked From
Curt RVi Series 4 Portable Flat Tow Brake System - Wireless Monitor - Proportional
- Flat Tow Brake System
- Brake Systems
- Proportional System
- Every-Trip Setup
- 12V Outlet
- Portable System
- Air Brakes
- Air Over Hydraulic Brakes
- Hydraulic Brakes
- Wireless Display
- CURT
more information >
Featured Help Information
Instructions
Continue Researching
- Shop: Vehicle Tow Bar Wiring
- Shop: Base Plate for Tow Bar
- Shop: Vehicle Tow Bar Brake System
- Video: Review of Roadmaster Smart Diode for LED Tail Lights - RM24DQ
- Video: Roadmaster Smart Diode Kit Installation - 2025 Jeep Wrangler Unlimited
- Search Results: tow bar
- Search Results: air force one braking system
- Search Results: trailer hitch
- Search Results: trailer wiring
- Search Results: hitch receiver
- Search Results: trailer hitch receiver
- Search Results: hitch
- Shop: Replacement Roadmaster Smart Diode for LED Tail Lights - Qty 1
- Shop: Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights
- Shop: Replacement Roadmaster Smart Diode for Incandescent Tail Lights - Qty 1
- Video: Demco Air Force One Flat Tow Brake System Second Vehicle Kit Install - 2025 Jeep Wrangler Unlimited
- Shop: TowSmart 4-Way Flat Trailer Connector w/ 48" Harness
- Shop: Towed Vehicle Reinstall Kit for Demco Air Force One Flat Tow Brake System
- Video: Mount: Roadmaster InvisiBrake Flat Tow Brake System on a 2021 Jeep Wrangler
- Shop: Trailer Hitch
- Video: Curt RVi Series Shadow 2 Flat Tow Brake System DIY Install - 2025 Jeep Wrangler
- Video: Installation Guide for the Demco Air Force One Flat Tow Brake System Reinstall Kit - 2024 GMC Canyon
- Shop: Roadmaster Stop Light Switch Kit
- Shop: Roadmaster Nighthawk All-Terrain Tow Bar w/ LED Lights - Non-Binding - RV Mount - 8,000 lbs
- Video: Demco SBS Air Force One Second Vehicle Kit Installation - 2022 Jeep Wrangler Unlimited
- Q&A: What Gauge Wire does 4-Way Trailer Wiring Use
- Article: Flat Towing Package for 2007-2018 JK Jeep Wrangler and Wrangler Unlimited
- Q&A: Parts Needed For Flat Towing a 2017 Jeep Wrangler Unlimited Rubicon
- Shop: Performance Chip Tuners
- Shop: Vehicle Cargo Control
on Flat Tow Brake System
Jon Y.
10/9/2025
Thank you. For future reference, I performed the tests, and the 2025 Jeep, 4-door, Rubicon does seem to require a brake relay. The brake lights do operate without the ignition being on and they also share brake lights and turn signal lights.