How To Tell If My Jeep Needs A Brake Light Relay When Flat Towing
Updated 10/09/2025 | Published 10/07/2025
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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 RVibrake 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 >
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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.