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Brake Controller Installation: Starting from Scratch

Custom Fit Trailer Brake Controller

Before Installation You Will Need:

  1. Brake Controller
  2. 7-Way Installation Kit (#ETBC7)
  3. 4-Pole Trailer Connector (if not already installed)

Information About 7-Way and 6-Way Installation Kits

The 7-way Trailer Connector Has a Total of Seven Wires:

The Colors of the Remaining Four Wires:

The ETBC7 and ETBC6 Installation Kits:

All the parts necessary to connect a brake controller to your vehicle are included

The 7-way installation kit pictured with all included parts

The 7-Way Installation Kit Parts

  1. 7-way trailer connector, which includes a 4-pole adapter
  2. The mounting bracket secures to the vehicle's bumper or other appropriate mounting location and harbors the trailer connector.
    • Mounting hardware, such as self-tapping screws, is included to mount the bracket to the vehicle and the trailer connector to the bracket.
  3. The gray duplex cable houses two wires that will become the 12 volt hot lead and brake wire.
    • The duplex cable runs from the trailer connector to the front of the vehicle.
  4. The black loom is a hard plastic tube that covers the 12 volt hot lead and brake wire connections at the trailer connector, protecting the connections and giving your installation a professional appearance.
  5. Circuit breakers act as midway connections for the 12 volt hot lead and the brake controller power supply (introduced later) before they reach the vehicle's battery.
  6. Butt connectors help to make connections between wires.
  7. Ring terminals attach to the end of wires and hook around battery posts and circuit breakers.
  8. Zip ties help to bind loose wires together and prevent them from interfering with vehicle components such as brake and gas pedals.

Brake Controller Installations Steps

The duplex cable has been run towards the firewall at the front of the vehicle.

Installing and Wiring the 7-Way Trailer Connector

  1. Find a suitable location to mount the 7-way connector.
    • A typical location is on the bottom of the bumper.
    • Using the self-tapping screws, secure the mounting bracket into the bumper and the trailer connector into the bracket.
  2. Plug the 4-pole adapter coming out of the 7-way connector into the vehicle's 4-pole trailer connector.
  3. Ground the 7-way connector by screwing the white wire into the frame of the vehicle.
  4. Make a small cut in the rubber sheath of the duplex cable and slightly separate the two wires inside.
    • Use a butt connector to connect the black wire in the duplex cable to the 12 volt hot lead (black wire on the 7-way connector).
    • Then do the same for the white wire in the duplex cable and the brake wire (blue wire on the 7-way connector).
    • Next, route the duplex cable under the vehicle all the way up to the engine compartment under the hood, being careful to avoid hot areas or those that may pinch the cable.
    • Before you proceed further, the brake controller needs to be mounted.
      • We will return to the duplex cable shortly.

Brake controller sitting flush on the lower right side of the dash

Mounting the Brake Controller

  1. Choose an appropriate mounting location for the brake controller mounting bracket.
    • A typical location is the lower right side of the dash, which allows easy access to the brake controller in the event of an emergency braking situation.
  2. Using the screws provided, install the mounting bracket into the dash.
    • Make sure you avoid drilling through components on the other side of the dash.
  3. Secure the brake controller into the mounting bracket.
  4. The four wires on the brake controller will be connected shortly.

The 12 volt hot lead and trailer feed have been separated before running through the firewall.

Wiring the 7-Way Trailer Connector and Brake Controller

1. Return to the duplex cable under the hood, where the brake wire (now white) needs to be separated from the 12 volt hot lead (black).

Circuit breakers mounted in the engine compartment

2. Using a butt connector, connect the blue wire coming out of the brake controller to the brake wire (white wire of the duplex cable) that was routed through the firewall.

3. Find a safe location under the hood or on the firewall to mount two circuit breakers: one 20-amp (or 30-amp; see brake controller instructions) and one 40-amp.

4. The black wire coming out of the brake controller is the brake controller power supply.

View of wires attached to positive and negative posts on battery

Brake switch wires located above the brake pedal

5. The white wire coming out of the brake controller is the ground wire.

6. Inside the cab, we only have one connection remaining.

7. With the brake controller mounted and connected, zip tie any loose, excess wires underneath the dash and under the vehicle.

brake control wiring diagram

Dave M.


installing a 7pin trailer connector and brake controller on my 1998 Tahoe. There is a orange and blue (#10 size) wire folded back and taped off in the factory trailer harness cable (ORN -PWR and BLU DRK - AUX) Is either of these the wires that go to the brake controller connection thats under the dash. I have not started the controller install yet, was hooking up the 7 pin plug first.

David B.


Dave, the best way is to test the wires; then go through the basic testing procedures listed in the linked article.

Tractor D.


@DaveM I think the blue is brake and the orange is a charge lead. Did you ever find out?
Etrailer Expert

Mike L.


The blue and orange wires mentioned ARE intended for the installation of a brake controller. The blue wire is intended for the output from the brake controller to the 7-way trailer connector, and the orange wire is intended to supply 12-v power from the vehicle battery to the 7-way trailer connector. The wires run along the driver's side frame rail from behind the rear wheel and terminate under the master cylinder/brake booster.

Mick O.


Hi, I have a 2011 F150 with factory brake controller. When I connect a braked trailer and apply the brakes the stop lamps are dim when applied and it has blown the fuse before. when using the manual override the turn signals light up and not the stop lamps? any help would be hugely appreciated Cheers Mick

David B.


The dim lights is a bad ground connection or a short. If the turn signal is lighting up I would get a circuit tester and check the function of the circuits at the vehicle and trailer connection. Sounds like something is wired backwards.

Warren Z.


I installed your ETBC7 kit using your 5535 draw-tite brake controller and 20127 plug in harness on my 1994 chev silverado K-1500. The lights on my truck and car trailer work O.K. until I put my foot on the brake petal, my 15 amp turnsignal / stop light fuse blows. I tried disconnecting the red stoplight wire from the stoplight switch. still have same problem. Can you help me solve this problem?

David B.


If your breaker keeps blowing you have a short somewhere, so get that circuit tester out and start searching for that short! Also make sure you are using the right size fuse/breakers.



I have a 2013 Ford Expedition XLT and hooking up a Hopkins Towing Solutions Multi-Tow 4 Flat to 7 Blade and 4 Flat Adapter, 47185. I also will be using a CURT 51180 Echo Mobile Electric Trailer Brake Controller with Bluetooth-Enabled Smartphone Connection, Proportional for my brake controller. I will be using for my camper. On the 7 pin connector hookup. Following the instructions with the installation I connect the 4 pin pre-wire to the one on my truck and also installed the white wire ground form the 7 pin to my vehicle frame. 1. Do I need to hook up the purple to the reverse since I will be using for my camper 2. Should I hook up the Auxiliary black wire to the battery? If so I will need to run a wire back to the battery and use an auto circuit breaker? 3. On my wire harness on the vehicle has the separate Electric Brake wire is cap off. Should I hook it up to the blue wire even if I will not be using a Brake controller inside the vehicle but using the Echo Mobile Electric Trailer? I do hook the wires up can I just leave it connected?

Les D.


Regarding the wire for 12 volt trailer accessory, the wire for brakes, and the wire for a back up circuit, if it were me, I would hook up all wires provided, and fuse them as necessary. This trailer will not be the last thing you tow, and if you are going to the trouble to have a standard 7-way round connector, I would set it up for standard RV use. But to answer your question, based on your intended use, you would not have to use the blue wire brake controller out put, nor the purple reverse circuit. The Curt bluetooth brake controller does require the 12 volt accessory line to be powered.



@LesD Thanks for the response. I did hook up all the wires except the purple reverse wire for now, but I plan on also installing to have all the wires for possible future usage and/or if I sell the vehicle. I just have to figure which wire on my vehicle rear lights to connect the purple wire. On the 12 volt trailer assessory, I installed a 10 gauge primary wire from the 7 pin to the battery with a 40 amp auto reset breaker. Tested all wires and verify working. Good to go.

Les D.


@Danny that sounds good. Happy Camping!

David M.


I am installing a class lV hitch on my 2022 Subaru Outback and need to install 7 way trailer plug. Would like the plug to have screw wire connectors on the back of the plug. The car has a pre wired connector for this prepose. I would like to get the correct wire harness to install. The trailer has tandom axles and brakes. I would like to install a proportional brake controller with a dash mounted controll knob. Could you help guide me to the correct parts? THANK YOU Dave M

Les D.


@DavidM for a 7-way connector socket which has screw down terminals you can use the Hopkins # HM48480 connector. Regarding a proportional dash mounted brake controller, I recommend the Tekonsha Primus IQ Trailer Brake Controller # TK90160. Although it can be a knee-knocker getting in and out of your vehicle, I like the smooth operation, and easy to use manual brake lever.



@LesD I've got the Primus IQ and am trying the find the brake signal wire to tap into on the 22 Outback. There're 5 wires that plug into the switch, white, yellow, black, blue/red, and green. Do you know which one it is?

David B.


Hey Sean, I would call or go over to your closest Subaru dealer and have them look at it or see if they can tell you the correct wire. If you don't want to do that you'll need to test the circuits for function.
See All (4) Replies to David M. ∨



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