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Brake Controller Installation: Starting from Scratch

Before Installation You Will Need:
Select your vehicle to confirm the Trailer Brake Controller fit
bc fitguide
Information About 7-Way and 6-Way Installation Kits The 7-way Trailer Connector Has a Total of Seven Wires:
  • Four of these wires need to be connected individually, and three lead to the 4-pole adapter.
  • The 4-pole adapter will plug into the vehicle's own 4-pole trailer connector, allowing for basic wiring functions without the hassle of splicing or cutting into your vehicle system.
  • The three basic wiring functions are for tail lights, stop lights and turn signals.
  • NOTE: This 4-pole installation is vehicle specific.
    • If your vehicle does not already have its own 4-pole trailer connector, use the Wiring Fitguide to find the harness recommended for your vehicle.
The Colors of the Remaining Four Wires:
  • The first wire (black) runs to the vehicle's battery to supply power to the trailer connector.
    • This wire is called the "12 volt hot lead."
  • The second wire (blue) runs to the brake controller to supply power to the trailer brakes.
    • This wire is called the "brake wire."
  • The third wire (white) gets grounded to the vehicle's frame.
    • This wire is called the "ground wire."
  • The fourth wire (yellow) hardwires to the vehicle's reverse lights.
    • This wire is included with 7-way connectors but not 6-way connectors and can be tied off if it is not going to be used.
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 Parts
  • 7-way trailer connector, which includes a 4-pole adapter
  • 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.
  • 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.
  • 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.
  • 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.
  • Butt connectors help to make connections between wires.
  • Ring terminals attach to the end of wires and hook around battery posts and circuit breakers.
  • Zip ties help to bind loose wires together and prevent them from interfering with vehicle components such as brake and gas pedals.
installation kit
Brake Controller Installations Steps
Installing and Wiring the 7-Way Trailer Connector
  • 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.
  • Plug the 4-pole adapter coming out of the 7-way connector into the vehicle's 4-pole trailer connector.
  • Ground the 7-way connector by screwing the white wire into the frame of the vehicle.
  • 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 wiring
Mounting the Brake Controller
  • 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.
  • 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.
  • Secure the brake controller into the mounting bracket.
  • The four wires on the brake controller will be connected shortly.
mounting your bc
Wiring the 7-Way Trailer Connector and Brake Controller
  • 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).
    • The 12 volt hot lead will stay under the hood, where it will be connected to the positive post of the battery via a 40-amp circuit breaker.
    • The brake wire will be routed through the firewall into the vehicle, where it will later be connected to the brake controller.
    • It is best to run the brake wire through an existing grommet or knockout in the firewall.
    • If none is found, a hole can be drilled.
    • Make sure both sides of the firewall are clear of obstruction before drilling.
  • 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.
  • 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.
    • After those are secured, route the 12 volt hot lead to the 40-amp breaker via ring terminals and then to the positive post on the battery.
  • The black wire coming out of the brake controller is the brake controller power supply.
    • Route this wire to a 20-amp (or 30-amp) breaker under the hood and then to the positive post on the battery.
    • There are now two wires connected to the positive post: the 12 volt hot lead and the brake controller power supply.
    • NOTE: There will be excess wire after the 12 volt hot lead or brake wire connections have been made.
      • If any brake controller wires are too short, use the excess wire from the 12 volt hot lead or brake wire to lengthen them as needed.
  • The white wire coming out of the brake controller is the ground wire.
    • Route this wire to the negative post on the battery.
    • It will be too short to reach the battery, so you will have to use excess wire from the 12 volt hot lead or brake wire to complete this connection.
  • Inside the cab, we only have one connection remaining.
    • Find the wires connected to the brake switch at the top of the brake pedal.
    • Using a circuit tester, find the wire carrying a signal when the brake pedal is engaged.
    • Use a quick splice to connect this wire to the red wire coming out of the brake controller.
  • With the brake controller mounted and connected, zip tie any loose, excess wires underneath the dash and under the vehicle.
    • DO NOT allow the wires to interfere with the brake and gas pedals, and keep them away from areas of excessive heat.
wiring bc 1
wiring bc 2
wiring bc 3
wiring bc 4
diagram
Updated by: Jacob JLast Updated on: 3/14/2023

Marcel F.

10/31/2023

I have the Curt echo wireless brake controller. How would the wiring be different when I use this kit?

Etrailer Expert

Mike L.

11/15/2023

@MarcelF What you'll really need is the # ETBC7L. The only difference is the # ETBC7 has a duplex cable that's ran to the front of the vehicle, while the # ETBC7L has a single wire. The wires ran to the front on the # ETBC7 carry the 12V feed to the trailer and the brake controller output. For the # C51180 Echo brake controller, you don't need that output wire. Hope that helps explain it!

Dave D.

9/14/2023

Installing Tekonsha P3 controller in a 2008 Tahoe with factory wiring. Have searched the videos and articles/reviews for details on where to wire in the 20 amp circuit breaker. Can it be mounted under dash between the black controller wire and the red w/ black stripe Tahoe wire?? Or, should it be mounted to the fender under the hood, and wired into the brake control power wire going to the larger post?? Thanks for any help!

Etrailer Expert

Mike L.

9/14/2023

@DaveD The tow package harness you'll connect the controller to is already fused, so you won't need a breaker. The linked article will explain the install for you, check it out!

Carl

8/29/2023

I’ve got a 2007 Gmc 2500. The original control box was sending 12.49V to the 7 blade connection Blue wire at the back of the truck. I bought a new control box and upon installation delivered that the white wire ground feeding the original control box had come loose. Thinking that was the problem with the first box, I reconnected the white wire feeding box and checked voltage again. Now the blue wire at the back of the truck (in the 7 way truck connector) has 6.30 v all the time. I’m I correct in saying if the brake pedal is not pressed nor the “emergency” or manual switch on control box is not pressed, there shouldn’t be any voltage to the truck rear plug??

Carl

8/29/2023

@Carl *I meant to say that the control box was sending 12.49v to the trailer all the time.
Etrailer Expert

Mike L.

8/30/2023

@Carl Not sure what you mean by 'control box', are you speaking of the OEM brake controller? You'll see a volt or two at the output pin without the manual switch, which is the controller 'checking' to see if a trailer is connected. You shouldn't see full voltage. If you ARE speaking of an OEM controller, I'd suggest replacing it with an aftermarket model, because the OEM controllers back then weren't very reliable. The Tekonsha # TK90160 would be a good choice.
Etrailer Expert

Mike L.

8/30/2023

@Carl It might sound like a dumb question, but which pin are you getting the voltage at? The brake output pin is in the 5:00 position.

Larry

8/27/2023

87 chev c/k silverado

Etrailer Expert

Mike L.

8/30/2023

@Larry You can get the brake signal from either the 3rd brake lamp circuit or the 'NAT' terminal on the fuse box located behind the e-brake pedal.

Larry

8/27/2023

Where can I tap into the white wire ( cold side) to add a brake trailer controller?

Etrailer Expert

Mike L.

8/30/2023

@Larry For an '87 GM truck, look at the fuse panel located in the foot well behind the e-brake pedal. Look for a male push connector labelled 'NAT'. If you use a circuit tester like # PTW2993 on that connector, and it powers up with the brake pedal pressed you can install a female push connector on the red brake controller wire and make your connection there. If you can't find that terminal on the fuse box, or if it doesn't show a brake signal, you can tap into the 3rd brake lamp circuit instead.


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