Do I Need a Brake Light Relay When Flat Towing a 2026 Jeep Grand Cherokee?
Updated 08/27/2026 | Published 08/21/2026
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Question:
Flat tow Vehicle: 2026 Jeep Grand Cherokee Summit When using the Blue Ox Patriot Portable Flat Tow Brake System: Do I need to disable/modify the vehicle brake light when installing the Blue Ox 4-Diode Universal Tail Light Wiring Kit for Towed Vehicles
asked by: Ernie G
Expert Reply:
Hello Ernie,
Great question. I can't give you a direct answer, but I can tell you want to do to find out. It all depends on whether the brake lights on your 2026 Jeep Grand Cherokee Summit come on when the brake pedal is pressed with the Jeep set up in flat-tow mode.
The Blue Ox Patriot Portable Flat Tow Brake System # BLU37TR physically presses the Jeep's brake pedal. If that causes the Jeep's factory brake lights to illuminate, they can override the turn signal coming from the motorhome through the Blue Ox 4-Diode Universal Tail Light Wiring Kit # BX8848. If your brake lights do come on in flat-tow mode, you will need the Roadmaster Brake-Lite Relay Kit # RM-88400. The relay prevents the Jeep's brake light signal from overriding the motorhome's turn signal while you're towing.
If the Jeep's brake lights do not illuminate when the brake pedal is pressed in the required flat-tow mode, then the relay is not needed. I would set the Jeep up exactly as the owner's manual specifies for recreational towing and test the brake pedal before adding the relay.
Where is the first big trip after you get everything set-up?
Product Page this Question was Asked From
Blue Ox 4-Diode Universal Tail Light Wiring Kit for Towed Vehicles
- Flat Tow Wiring Harness
- Splices into Vehicle Wiring
- Diode Kit
- Universal Fit
- Blue Ox
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on Flat Tow Wiring Harness
Mal
8/26/2026
No, you do not have to modify the vehicle break light system. Wire as directed, and it will work fine. You will get the break or tail light when giving a turn signal as opposed to the different color and location of the vehicle turn light. The vehicle's turn signal will work as prior to install of the kit.