Do I Need to Use the Roadmaster Brake-Lite Relay when Flat-Towing My 2021 Jeep Wrangler?

Question:

do I need the Roadmaster brake light relay when flat towing my 2021 Jeep Wrangler with push start button?

asked by: Dean D

Expert Reply:

In order to determine whether you need the Roadmaster Brake-Lite Relay # RM-88400 when flat-towing your 2021 Jeep Wrangler with push-button start, it really depends on your towing setup. In order to confirm whether you do need the relay, consider these 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 determine that the brake light relay is needed, you will need to use the normally closed installation style since you have a push-start button on your vehicle. I went ahead and attached a diagram of the wiring setup and instructions for that particular method. In addition to the relay, you will need the Deka Heat Shrink Butt Connector - 16-14 Gauge - Nylon Insulation # DW05744-5.