What Wiring and Brake Controller do I Need for My 2005 Ford F-150 with 4 Flat Wiring?

Updated 08/18/2025 | Published 08/01/2025

Products Featured in This Question

Tekonsha Prodigy P3 Trailer Brake Controller w/ Custom Harness - Up to 4 Axles - Proportional

(6643)

$206.93

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

(3397)

$121.25

Question:

Dear Team, The ion of products is vast. Can you recommend a common set up to add a brake controller and convert my factory flat to a 7 way round connector. Tow vehicle is a 2005 F-150 4.6L V8 XTL. I prefer hard wired vs wireless.

asked by: Joe T

Expert Reply:

Hello Joe,

Since your 2005 Ford F-150 already has the 4 flat wiring, you will need to build on top of that by installing the Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires # ETBC7. To install the # ETBC7 you will need to run a power cord from your battery with a couple of amps along the way, and run a brake wire from the front to the rear as well. I attached an install video so you can see exactly what needs to be done.

For a brake controller, looks like you were already checking out my go to, the Tekonsha Prodigy P3 Trailer Brake Controller w/ Custom Harness - Up to 4 Axles - Proportional # TK23HR. The # TK23HR will come with the vehicle specific pigtail for a simple install. I really like the P3 because it works with all the different brakes on a trailer, even the electric over hydraulic, giving you peace of mind that you are ready for any trailer you have to move.

What kind of trailer are you going to be towing that you are getting a brake controller set-up for?

expert reply by: Kate F

ETBC7 Wiring Diagram
(click to enlarge)

Joe T.

8/6/2025

Kate, I am towing a Rockwood Roo 2011 with a 7 way connector. The only portion of the wiring diagram that is unclear to me is the red wire from the brake control. What is the "cold side of the brake switch" referring too ? Joe

Kate F.

8/7/2025

@JoeT The “cold side of the brake switch” refers to the wire on the brake pedal switch that only gets power when the brake pedal is pressed and the ignition is on. This is where you connect the red wire from your brake controller so it only activates when you're driving and applying the brakes, preventing unnecessary battery drain. You can find it by using a something like a Hook Probe Circuit Tester # PTW2993 under the dash near the brake pedal to test the wires.

Joe T.

8/11/2025

Kate, Thank you for the help and clarification. I waiting on some tap connectors to finish the job but the brake controller and the new 7 way connector are mounted. The diagram above shows two circuit breakers, but the kit I purchased only has one and the generic diagram with the kit only shows one. Do you recommend two ? Joe

Kate F.

8/11/2025

@JoeT It looks like you purchased the # ETBC7L, if you are looking to use a wireless brake controller like the Curt Echo # C51180, you will just follow the instructions that you received and install (1) amp circuit breaker. If you are looking to use a wired brake controller like the Tekonsha P3 # TK23HR then you will need to install (2) amp circuit breakers and run brake wire from the front to the rear 7 way. The # ETBC7L is for wireless brake controllers, the # ETBC7 kit is for wired in brake controllers, that is why it comes with the brake wire and additional amp.

Joe T.

8/11/2025

@KateF ok I didn’t realize that at the time of the purchase. I’ll follow the diagram you provided in this thread and install the additional breaker.

Joe

8/16/2025

@KateF Just to confirm. Yes I purchased etbc7L and prodigy p3. Can I purchase the needed length of gxl wire and complete all connections on the diagram you attached? The breaker sizes on the diagram do not correspond to the 12 awg wire on the prodigy p3 or the etbc7L. Can I purchase 12 awg gxl wire and 20 amp breakers to make this work? A 40 amp breaker will not protect the circuit. Thank you for answering all my questions! Joe