How To Upgrade 4-Flat Trailer Connector To Work With Electric Brakes
Updated 09/02/2025 | Published 06/27/2025
Products Featured in This Question
Question:
I installed the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector with my receiver and I am wondering what you suggest if I want to upgrade my connection to accommodate a trailer with brakes.
asked by: Josh
Expert Reply:
Hey Josh, thanks for reaching out. We actually custom make our own wiring kit specifically for this purpose. What you will need is the following:
- Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires # ETBC7
This kit is made specifically to be used on vehicles with an existing 4-flat trailer connecter. It contains everything needed to upgrade the 4-flat to a 7-way which is what you need for a trailer with brakes. It also contains the necessary wires for a brake controller, which will be required.
For the brake controller I recommend the Redarc Tow Pro Liberty # RED52VR. It installs behind the dash, and all you see is the small LED control knob. It will install using the included universal pigtail.
I have included links to a few of our install videos, as well as a few pictures you should find helpful.
What kind of trailer will you be pulling? Just curious because it looks like you might have a ProMaster van and sometimes those setups are pretty cool
(click to enlarge)
(click to enlarge)
Product Page this Question was Asked From
Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires
- Accessories and Parts
- Trailer Brake Controller
- Installation Kits
- etrailer
more information >
Featured Help Information
Instructions
Miscellaneous Media
Continue Researching
- Search Results: generator carrier
- Search Results: brake controller
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Q&A: Why a 30A Breaker on 12V Feed for Curt Echo Brake Controller When Brake Magnets Only Use 4A Each
- Shop: Manual Override Button for Curt Echo Brake Controller
- Shop: Curt Echo Wireless Brake Controller - 7-Way Plug-in w/ Bluetooth App - Up to 2 Axles - Proportional
- Shop: Brake Controller
- Video: How to Install: Curt Echo Wireless Brake Controller on your 2020 Subaru Outback Wagon
- Q&A: Wiring for Curt Echo Mobile Wireless Brake Controller and Adding Electric Brakes to a Trailer
- Shop: Westlake ST235/75R15 Radial Off-Road Trailer Tire - Load Range D
- Shop: 40 Amp In-Line Circuit Breaker - Perpendicular Mount Bracket
- Shop: Trailer Wiring
- Shop: Roof Rack
- Shop: Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires
- Shop: Curt 7-Way to RV Socket LED Circuit Tester - Vehicle End
- Shop: Curt True Course Advanced Bluetooth Trailer Sway Control - 1 to 4 Axles
- Article: Brake Controller Installation: Starting from Scratch
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Article: Trailer Wiring Diagrams
- Q&A: What is the Difference Between a 4-Way and 7-Way Trailer Connector
- Q&A: My Vehicle has a 4-Pin Trailer Plug, but Trailer has 7-Pin Trailer Plug
- Article: How to Measure for Trailer Hitch Drop
- Article: Towing a Trailer? Let's Talk About Brake Controllers
- Q&A: What is the Difference Between a Class II and a Class III Hitch?
- Article: How to Choose the Right Trailer Hitch Class
- Q&A: What is the Difference Between the Tekonsha Prodigy P2 and the P3 Brake Controllers
- Q&A: What Hitch Will Fit My 2012 GMC Savana 3500 4.8L V8 Built on a Cutaway Chassis?
Jesse M.
9/2/2025
Hey Josh, did you get a chance to install the Universal Installation Kit and the Redarc Tow Pro Liberty brake controller? How did it work out with your trailer setup? I'm asking because your experience could really help others looking to upgrade their trailer connections.