Can Tow Bar Wiring and Trailer Wiring Install at Same Time On 2025 Jeep Wrangler

Updated 12/29/2025 | Published 12/14/2025

Question:

Hi - I purchased a complete flat tow system for my 2025 Jeep Wrangler Unlimited JL which includes e-trailer part RM477ZR - smart diode system. My Jeep did not come with a rear hitch or wiring, which I intend to install both parts available from Quadratec. The Quadatec wiring harness for that rear hitch is : 92015-8004, which is a plug-and-play installation. My question is, does it matter where the smart diode wiring gets spliced into the brake/hitch wiring? I.e. do I install the smart diode at some point above the hitch wiring harness?

asked by: Lee R

Expert Reply:

Hey Lee, that's a great question but it doesn't matter where the lighting kit part # RM47ZR wires in relation to the trailer wiring. As long as both are installed on the right circuits everything will work great together. Do you think you'll ever attempt to tow the Wrangler while it's towing a trailer?

expert reply by: Jameson C

Lee R.

12/15/2025

Jameson - thank you for the quick response! The Jeep trailer hitch will be for a bike rack. Our e-bikes are covered during travel so it’s necessary to have lights on the bike rack. Thanks again for the instructions. Lee

Jameson C.

12/15/2025

@LeeR Glad to help!

Brent

12/16/2025

@LeeR Watch Roadmaster Smart Diodes Wiring Kit Installation Guide - 2023 Jeep Wrangler 4xe Video on trailer.com, starting at about 12 minutes to see how to splice into brake light wiring. Probably consistent or similar to your 2025.

Jameson C.

12/16/2025

@Brent Thats awesome advice, thank you for sharing that!

Richard

12/16/2025

I installed the diode kit on our 2023 Jeep gladiator that has the LED tail lights. I removed the left rear tail light first, made the initial connections there and then ran the wire across/under the bed to the right tail light and made the remaining connections. We have now flat towed for about 8000 miles with no issues. We also have hitch mounted E bikes that we carry. While I have not set up any lights on the bike rack itself, I did buy a cover for the bikes, which I wrap very tight to where my tail lights are still visible. I did try magnetic mount trailer lights to stick on the bike rack, but that did not work and they constantly fell off due to the bike, cover hitting them.

Don B.

12/25/2025

My diodes were not installed properly on my 2022 Jeep Cherokee Trailhawk. Installer missed the instructions to link the brake light signal to the tail lights. I'm not convinced I like using the tail light for braking signals (but haven't tried it). The other problem is that the Jeep brake lights come on when the supplemental braking system activates the brakes, which kills the turn signals. Finally because of chip shortages my Jeep did not come with Parking Assist sensors which sometimes confuses the selection of the correct diodes. Also I have never been able to find any technical information on rear lighting voltages from Jeep, eTrailer, Blue Ox, or Demco.

Jameson C.

12/29/2025

@DonB Sorry to hear about all the issues you've had with the tow bar lighting setup you have. Since your braking system overrides your turn signals what you need is a brake light relay part # RM-88400 which is designed address and fix this exact problem.