What Wiring and Brake Controller do I Need for My 2018 Ford F-150 with Factory 4 Flat?
Updated 05/12/2026 | Published 05/02/2026
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Question:
I currently have a 2018 f-150 with a 4-flat factory installed, i am looking to replace that with a 7-pin/4-flat combo with a trailer brake controller, could you help me find all of them that all work together please.
asked by: casey h
Expert Reply:
Hello Casey,
Thanks for reaching out, I’m glad you found us!
Since your 2018 F-150 already has the factory 4-flat, you’re in a great spot to upgrade to a 7-pin/4-flat combo, and the nice part is you won’t need the # ETBC7L you were originally looking at.
What you’ll want to start with is the Curt T-Connector Vehicle Wiring Harness with 7-Way Trailer Connector # C56413. This is a plug-and-play option designed for your truck that will give you a 7-way connection at the rear by tying into your factory wiring.
To get the 7-pin/4-flat combo you’re looking for, you can then pair that with the TowSmart ProClass Multi-Tow 7-Way and 4-Way Flat Trailer Connector - Vehicle End # TS87RR. This plugs right into the harness from the # C56413 and gives you both connectors in one combined socket.
We don’t currently have images of the # TS87RR on the product page, but I had one nearby so I grabbed a couple pictures for you. I really like this style because both covers can open at the same time, which most others won’t do.
For a brake controller I would go with the Redarc Tow-Pro Liberty Brake Controller w/ Custom Harness - Dash Knob - Up to 2 Axles - Proportional # RED67CR. I really like this brake controller because the adjuster is at arms reach, and it also works with electric over hydraulic brakes, not all of them do. It will also come with the vehicle specific pigtail for an easy install.
What kind of trailer are you looking to pull that has brakes, and what kind of brakes does it have?
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Jeffrey R.
5/7/2026
I purchased this kit to install in a 2025 outback wilderness which had a factory flat 4 plug. This is a very easy product to install and basically just utilized a modular 4 pin flat integrated cable to plug into the legacy outlet. It does require that you tie down a ground wire to frame and also requires connecting a wire from the plug to a relay block which gets mounted in the engine bay and then requires a wire from that relay block to the + battery terminal for 12v dc power. I used a curt Bluetooth brake controller which just plugs into the new power outlet and it worked great! A couple of things to know. 1) The wire provided for the 12V connection between the rear of the vehicle and the battery/relay block is not nearly long enough so be prepared to supply a small spool of your own to avoid coming up short. 2) The other thing to note is that although the actual plug unit seems to be very well built, the hardware provided to mount the connector to the car is really bad quality. I purchased the unit and mounted it October 31 2025 and traded my car in April and when I went to remove the connector the screws were so badly rusted I had to drill them out to remove the connector from the bracket. In the future I plan to reuse this adapter because it works very well but will source stainless misc hardware to avoid this issue in the future. Had the kit included an additional 20ft of wire over what’s current provided and stainless mounting hardware I would give it a 5/5 . As is 4/5
Kate F.
5/8/2026
Product Page this Question was Asked From
7-Way RV Upgrade Kit for Trailer Brake Controller Installation - 12 Gauge Wires
- Accessories and Parts
- Trailer Brake Controller
- Installation Kits
- etrailer
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Casey H.
5/7/2026
Hi Kate, I’ll be pulling a 16’ enclosed trailer and a 20’ enclosed car trailer I know the 16’ is electric, I believe the 20 foot is electric as well, both double axle