Where Does The Red Wire Install to On the Roadmaster Brake-Lite Relay Kit 2007 Hummer H3
Updated 03/04/2026 | Published 02/21/2026
Question:
I am installing a Roadmaster brake light relay RM 88400 on a 2019 f 150. Does the red wire connect to the brown wire from the motorhome? Thanks
asked by: Jerry W
Expert Reply:
Hey, Jerry.
Since your Hummer is a 2007, I’m going to assume it has a key-start ignition. For that setup, the red wire on the Roadmaster Brake-Lite Relay Kit, part # RM-88400, will connect to the fuse tap. I’ve included the steps for that portion of the install below, along with the diagram for reference.
- Insert the fuse you just removed into the slot closest to the fuse blades (Figure 2).
- Then insert the fuse tap into the empty slot in the fuse panel (Figure 1).
- Using the attached blue butt connector, connect the red wire from the Brake-Lite Relay to the wire from the fuse tap (Figure 1).
Is this your first time getting into flat towing, or are you just switching up the vehicle you’re towing?
(click to enlarge)
Product Page this Question was Asked From
Roadmaster Brake-Lite Relay Kit for Towed Vehicles
- Flat Tow Brake System
- Brake Light Relay
- Roadmaster
more information >
Featured Help Information
Instructions
Continue Researching
- Shop: Gooseneck Hitch
- Shop: B&W Turnoverball Underbed Gooseneck Trailer Hitch w/ Custom Installation Kit - 30,000 lbs
- Shop: B&W Rubber Cover for Stowed Turnoverball
- Video: Review of B and W Gooseneck Hitch - Ford Superduty Turnoverball Gooseneck Trailer Hitch - BW73FR
- Video: B&W Turnoverball Underbed Gooseneck Trailer Hitch Installation Guide - 2025 Ford F-350 Super Duty
- Video: B&W Gooseneck Hitch Manufacturer Breakdown
- Shop: B&W Turnoverball Underbed Gooseneck Trailer Hitch w/ Custom Installation Kit - 30,000 lbs
- Shop: Curt Double Lock, Flip and Store Underbed Gooseneck Hitch w/ Installation Kit - 30,000 lbs
- Shop: B&W Turnoverball Underbed Gooseneck Trailer Hitch w/ Custom Installation Kit - 30,000 lbs
- Shop: B&W Turnoverball Underbed Gooseneck Trailer Hitch w/ Custom Installation Kit - 30,000 lbs
- Shop: Vehicle Tow Bar Brake System
- Shop: Roadmaster Brake-Lite Relay Kit for Towed Vehicles
- Q&A: What Is An OEM Prep Package And How Do I Know If I Have It
- Article: Trailer Wiring Diagrams
- Shop: Trailer Hitch
- Video: Fifth Wheel Towing Made Simple with Daniel
- Search Results: trailer hitch
- Shop: Trailer Wiring
- Article: How to Measure for Trailer Hitch Drop
- Search Results: trailer wiring
- Q&A: Installation Time for Blue Ox BX1128 Flat Tow Base Plate Kit for 2016 Jeep Grand Cherokee
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Search Results: trailer tires and wheels
- Video: B&W Companion OEM 5th Wheel Hitch Manufacturer Breakdown
- Shop: Suspension Enhancement
- Q&A: Gen-Y Gooseneck Pin Box for 2022 Forest River Cardinal Red With Rhino Box
- Q&A: Should I Get Loadlifter 5000 Or 7500 For Towing A 15K Fifth Wheel
- Search Results: gooseneck hitch
- Article: 4 Steps to Choosing Your 5th Wheel Pin Box
- Shop: Fifth Wheel Hitch
on Flat Tow Brake System
Roger M.
3/4/2026
everything installed and works as it's supposed to. I ran my wires through the firewall through a factory grommet, then along the left footwear and followed the factory harness under the sill guard and over the fenderwell to behind the left tail light module. Much cleaner than through frame rail. remaining wiring runs along rear frame structure inside wire loom tied down with zip ties.. The factory got the color code wiring for power backwards, power is power, everything works.