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Brake Controller Installation on a Full-Size Ford Truck or SUV

Installing a brake controller can sometimes seem like an overwhelming task, but even if you are starting from scratch and have no previous experience, it is definitely manageable. Now, many manufacturers run most of the wires for a brake controller at the factory, so all you have to do is plug into them—it's that easy. We'll cover how to install a brake controller on:
  • 1994–2004 Ford Full-Size Trucks (F-150, F-250, and F-350)
  • 2004–2008 Ford F-150
  • 1997–2011 Ford Expedition
  • 2000–2005 Ford Excursion
Teckonsha PRODIGY proportional brake controller

Custom Fit Brake Controller

Tekonsha PRODIGY proportional brake controller

Factory Installed 7-Way

If your full-size Ford truck or SUV already has the factory installed 7-Way trailer connector, the only part needed to install a brake controller is the brake controller itself. Usually, Ford provides with the truck an adapter that connects directly to the brake controller and to the OEM brake controller plug on the vehicle. The OEM plug is on the driver's side, behind the trim panel that runs below the steering wheel, and to the right of the driver's side, beside or behind the radio console. If you can't find the factory brake control adapter, you can get a replacement.

Begin by connecting the brake control adapter to the brake controller. The factory adapter may use different wire colors than the wires you see coming from the brake controller, but all of the wires should be labeled. The standard brake controller wire colors are white for ground, red for the stoplight switch connection, blue for the electric brake lead to the 6- or 7-Way plug, and black for the 12V brake controller power connection. You will connect the factory or aftermarket adapter to the brake controller according to function, using butt connectors.

Custom-fit adapters are available for many brake controllers. A custom-fit adapter has 2 plugs—one attaches to the plug on the brake controller and the other connects to the OEM plug under the dash.
To access the OEM plug, look near the diagnostic port on the underside of the dash. You should see an open-ended, gray plug hanging down near the diagnostic port (Figure 1A).
Ford brake controller wiring harness
If this plug cannot be found near the diagnostic port, remove the trim panel from below the steering column and look for a gray plug on the right side, near the center console and radio area. With the lower trim panel removed, look for the gray plug beside the sheet metal that runs along the driver's side of the radio area (Figure 1B). If it is not readily visible, you may need to check further inside of the dash, reaching through the sheet metal and into the area behind the center console.
Ford brake controller wiring harness near the diagnostic port

After locating the OEM plug and connecting the brake controller wiring to it, mount the brake controller to a place on the dash that is easily accessible. Typically, the controller would be mounted on the right side of the steering wheel, below the dash. The controller should be mounted comfortably within the driver's reach.

Once mounted, the brake controller installation is complete. See the owner's manual for tips on setting up the brake controller for safely towing your trailer and its load.

Brake controller installed in full-size Ford truck or SUV

Factory Installed 4-Way

If you drive one of the vehicles listed above and your vehicle has a factory installed 4-Way flat trailer connector, then only a few extra parts are required to equip the vehicle for towing a trailer with electric brakes.

  • A brake controller
  • A universal adapter, custom adapter (See installation procedure above), or the factory adapter if it is provided
  • A 4- to 6-Way (37175) or 4- to 7-Way (37185) adapter, or OEM style replacement 6-Way or 7-Way plug, if available.

Connecting the 6- or 7-Way Plug

After connecting and mounting the brake controller as in the steps above, start in the rear of the vehicle. Follow the 4-way trailer connector wires from the trailer connector to the front of the vehicle. These wires connect to a factory plug along the frame rail, usually on the driver's side, between the back tires and the rear bumper (Figure 2). The factory plug should be mated to another connector which has wiring that continues back toward the bumper.
Trailer wiring harness on driver's side rear frame of full-size Ford
There are more wires coming from the front of the vehicle than there are coming out toward the 4-Way plug (Figure 3). Ford wires the front of the vehicle as if it will be manufactured with a 7-Way plug, so all the 7-Way wires are run to this connector on the frame rail. This allows a 7-Way wiring harness to simply plug in line with the wiring coming from the front of the vehicle. If the vehicle were made with a 4-Way plug, it would plug into the same connector. Because a 4-Way plug would not require them, the additional wires are terminated at the pictured set of mated connectors.
Closeup of trailer wiring harness on driver's side rear frame of full-size Ford
The 7-Way and 6-Way adapter will come with a 4-Way trailer end that connects to the vehicle's 4-Way trailer connector, and four (4) or three (3) extra lead wires. The white wire is for the ground, the blue wire is for the trailer brakes, the black wire (7-Way) or red wire (6-Way) is for a "hot" lead coming back from the battery, and the orange or purple wire (7-Way adapter only) is for another auxiliary function, such as reverse lights.
4- to 6-way and 4- to 7-way trailer wiring adapters © etrailer

To install the 7-Way or 6-Way adapter, first plug in the 4-Way trailer connector on the adapter into the 4-Way connector on the vehicle. Next, snip the blue and orange Ford wires next to the plug coming from the front of the truck. Connect them to the blue and black wires on the adapter (Figure 4). Using a self-tapping screw, secure the white wire to the vehicle frame to ground the adapter. After mounting the adapter, installation is complete.

If you prefer not to cut the wires, a factory plug-in adapter is available for select vehicles:

  • 1997–2003 Ford F-150: 20028 (6-Way) or 118242 (7-Way)
  • 1997-1999 Ford F-250 Light Duty (Styleside): 20028 (6-Way) or 118242 (7-Way)
  • 1999–2001 Ford F-250 and F-350 Super Duty: 20029 (6-Way) or 118243 (7-Way)
  • 2004 Ford F-150 (New Body Style): 118247 (7-Way)
  • 2004 Ford F-150 Heritage (Old Body Style): 20028 (6-Way) or 118242 (7-Way)
    Ford trailer wiring on driver's side rear frame
    Note: You will want to use a circuit tester to confirm the function of each wire. We encountered blue and orange wires in our installations, but manufacturers have been known to switch colors. Your vehicle may also need additional fuses and/or relays installed to activate the wiring to the rear plugs. Check your owners manual or fuse block diagram and make sure all fuses and relays labeled for "Trailer Tow" are installed before testing the wires.

    Brandon K.


    Does this apply to a 2001 f550 7.3L. xL model ?

    Etrailer Expert

    Mike L.


    @BrandonK I'm assuming this is a cab/chassis truck, correct?

    Andrew G.


    Does this apply to new F-150's as well? Or do you have an updated tutorial?

    David B.


    What year/make/model do you have and what brake controller?



    I have a 2008 Super Duty E350 5.4l. On the frame rail there is a flat plug with 6 wires. Currently a 4 wire trailer harnedd is plugged into this. I have seen a wire assembly that will plug into this and has a 7Way and 4 way on the other end. Ford part nbr is 5l3Z-13A576-BA do you know if this will fit my van, i found it for a 2008 F250 superduty but do not see my van in the fitment chart...the wiring is identical Though

    Jon G.


    Since you have the factory 4-Way what you really need is the part # 37185 which will connect to your existing wiring. The Ford part that you referenced (which I'm pretty sure won't fit) only gets you part of the way there - you will still need to install a connector that has a US Car Connection on it.



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