Brake Controller Installation: Starting from Scratch

Custom Fit 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

Questions and Comments about this Article

Cody M.

Working on a 2013 Ford F550 with a Utility bed and hoist. Im trying to install a new 7 way plug and it was all going well except I can't seem to find my brake wire. All of my wires tested negative so I have to run wires from the LED lights to the pickup end itself. I found my brake wire I believe but still no power from the original harness. How do I run a new brake wire from the brake switch? Thanks 84532

Reply from Chris R.

Are you referring to the factory trailer harness on your F-550? The brake and turn signal circuit should be sent along the same wire (trailer wiring is combined), so I would test the wires you already found for the turn signals and see if they also carry power with the brake lights illuminated. 67718


Hi, I'm installing a Reese towpower 8508211 brake controller on a 2019 VW Jetta everything is pretty much done but the only problem I had when trying to connect the red wire to the brake switch there were no wires on the brake pedal so what I did, I tap in to one of the wires that runs to the brake tail lights that runs from front to back on the side of the door this wire only gets power when you press the brake pedal. On the brake co troller screen I get 2 dots and when I activated manually I get an N.C. on the screen I wounder if my installation is correct? Thank you 81507

Reply from Chris R.

Are you testing the controller with a trailer actually hooked up? The "N.C." means "no connection", so that would be a normal message if the trailer isn't plugged in. 66795

Reply from Miguel

@ChrisR Looks like I got them to work I had both wires from the brakes connected to positive and no ground, so now I have one positive and one ground to each brake, both tires are locking up on the air but not when I'm driving the car at 25mph I can barely feel the trailer to engage the breaks all this with a max (10 & b1)at the brake controller do you think this problem has to do with any wiring issue or I need to break in my new pads in order to performed to the fullest. Thank you for your help 66945

Reply from Chris R.

@Miguel If you have new, self-adjusting brake assemblies they may indeed just need to be broken in a bit. Take the trailer up to an empty parking lot and just engage those brakes a bunch - each time you do this they'll essentially adjust a bit more until you have ideal braking. 67231

Don J.

Brake sense color and location for 2004 mercury mountaineer premier 4.6l v8 awd 81140

Reply from Chris R.

If your Mercury Mountaineer has the factory 7-Way connector at the bumper there should be a built-in brake controller port behind the dash with which you can use the Plug-In Adapter # 3035-P (if you have a Tekonsha or Draw-Tite controller). I wasn't able to track down info on an exact location, but typically these ports are to the left of the steering column, hidden a bit behind the dash. You might even check with a local Ford dealer to see if they have any information on this. 66794

Charles B.

I have a 2019 canyon, I bought a hopkins impulse controller. Can you help with the wiring please. I have to use it in 2 days, please advise 80553

Reply from Chris R.

Your Hopkins Impulse controller can be wired right into the factory harness under the dash. There isn't a plug, but all the needed wires are already present. They should be labeled by function. Coming from the Impulse the red wire will go to the brake input circuit, the black wire is for 12V power, the blue wire is for brake output (to the trailer), and the white wire is for ground. 66359

Darby L.

What color wire do I need to tap on brake pedal of a 2008 Nissain Armada 78451

Reply from Chris R.

Based on my research it actually looks like your Armada should come equipped with a factory port for plugging in a brake controller (whether or not it has the tow package) - so you shouldn't need to look for the right brake switch wire for a hardwire install. For example if you're looking to install a Tekonsha controller like the Prodigy P2 # 90885 , you would just need the Adapter Harness # 3050-P for a plug-and-play install. If you don't have the tow package you would add the 7-Way Kit # N40975 . 63692

Reply from Darby L.

@ChrisR. Brak controller will not work with plug and play harness. That is why I am going to hard wire it. 63722

Reply from Chris R.

@DarbyL I see. I wish I could track down the right wire color for that circuit, but the best method will be to simply test the wiring behind the pedal to see which one only gets power when the brake pedal is depressed (and no power with any other function). This is where the red wire from the controller will connect. 63906


We have a 2019 Durango that does not have the towing package so I will need to wire directly, however I am unable to find the wire for the break sense (stoplight) switch. Do you happen to have the color and location of the wire? I have to assume it's in the wire panel just behind the ebrake pedal but I can't find any wire that is only hot when the break is depressed. 76749

Reply from Chris R.

I really wish I could track down the right wire color, however I wasn't able to find a diagram for your '19 Durango. On some vehicles finding the cold side of the brake light switch can be difficult- if you can't find a wire behind the brake pedal that only gets power with the brake pedal depressed, you might need to tap into the 3rd brake light or even use the Stop Light Switch Kit # RM-751449 for this signal. 62573


Does the connection from the brake light switch carry a ground or a positive 12volt to the controller. Would connection to the center mounted brake light on a ford transit work. How much currant does this connection draw as these are very light guage wires. 76486

Reply from Chris R.

If you're able to access the 3rd brake light and you find the circuit that only gets power when the brake pedal is depressed (and no power otherwise) then you can tap into that circuit for the controller's red wire. Sometimes this is necessary if there isn't an adequate wire to tap into behind the brake pedal. For 12V power (to actually power the controller) you'll need to connect directly to the battery in your Transit. 62412


Which color wire on my break pedal wires is the power to the brake. 2003 gmc Sonoma ext 3 door no tow package. 65059

Reply from Jason S.

I tried looking up your particular model for color. The closest vehicle I could find the color diagram for which I believe has the same wiring harness is the Chevy S10. On that model the wire color you'd be looking for is white. To confirm this or to diagnose your vehicle's brake wire, you will want to use a circuit tester like # PTW2992 to test the wire for power. You should only see power when the brake pedal is pressed and no power on the wire when the brake pedal is not. 55244

Dave L.

Thanks for the helpful article. Questions:1. The brake controller is wired directly to the battery in the diagram. I could postulate safety reasons for this i.e. not to lose brakes if the engine quits or needed to apply brakes with the truck off but Is it acceptable to wire to an accessory with appropriate relay switch position. Seems like you would have a good potential to drain the battery if you left the controller on with the vehicle off.2. You used circuit breakers in this application. Is there a reason that circuit breakers were used in lieu of cheaper / simpler fuses. Again I could postulate that maybe you would hope that the breaker would reset if the fault cleared and still retain brakes.....? But you would still lose the brakes for some period of time whether the breaker tripped or the fuse blew...…. 64941

Reply from Jacob H.

If the break controller is operating properly, it would take a very long time for it to have any affect on the battery. Using a breaker is so that instead of having to replace the fuse when ever it blows, the breaker will trip and reset. You shouldn't have any issues with fuses or breakers if everything is wired correctly. If the breaker is not resetting then it will need to be replaced just like a blown fuse. 55387



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