Best Way To Add 7-Way To 2018 Ford F-150

Updated 11/04/2025 | Published 01/28/2025

Products Featured in This Question

Curt T-Connector Vehicle Wiring Harness with 7-Way Trailer Connector

(135)

$75.37

Curt 4-Way Flat Trailer Connector w/ 60" Harness and Wire Taps

(127)

$16.52

Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires

(3398)

$121.17

Question:

2018 Ford F-150 without original tow package. Wired up the kit without difficulty but the lights are extremely dim, almost impossible to see. Hooked up the trailer to my other truck and the lights are bright like normal. Is this a grounding issue or something else?

asked by: Scott S

Expert Reply:

Hey Scott, thanks for reaching out. So the Curt T-Connector # C56413 you ordered is intended for vehicles with a factory 4-flat connection. It sounds like your 2018 F-150 does not have a factory trailer connector, which explains why the # C56413 is not working correctly. Your vehicle is missing the necessary OEM wiring components to make it work.

If you need to add a 7-way to your truck, it can be done, but you will have to do some wiring. Adding a 4-flat and 7way combo will be the best bet, and for that you can use the following:

- Curt 4-Way Flat Trailer Connector w/ 60" Harness and Wire Taps # C58044

- Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires # ETBC7

These two kits contain everything you need to add a 4-flat and 7-way to your truck, including all of the necessary wires for a brake controller, like the Tekonsha P3 # 90195. The videos I linked below will show you an few examples of installation. Feel free to reach out with any questions.

expert reply by: Jesse M

Jesse M.

11/3/2025

Hey Scott, how did things go after switching to the Curt 4-way and the universal 7-way kit for your F-150? Did that clear up the dim light issue you were seeing before? Your update could make it easier for others with the same wiring setup.

Scott S.

11/3/2025

@JesseM absolutely was a grounding issue. Thank you for the support. Took a grinder to the chassis and reconnected on bare metal and it's working fine.

Jesse M.

11/4/2025

@ScottS Ah ok glad to hear you got to the bottom of it! Grounds are an easy fix so that is like a best case scenario. Feel free to come back anytime you need anything!