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Adding a 7-Way and Brake Controller to a 2015 Ford Expedition with Factory 4-Way


I am considering the purchase of a 2015 Ford Expedition XLT with a Factory 4 pin connector. I will be using it to tow a lightweight travel trailer so I need to convert to 7 pin and add a TBC. I have read that Ford includes a 7 wire harness on all units from the factory with TBC connector under the dash and all I have to do is wire in this adapter along the rail. Do you know if this is accurate? Any help you can provide would be appreciated.


Expert Reply:

From what we have found the 2015 Ford Expedition that came with a factory 4-Way connector will need a little bit of hardwiring to install a brake controller and 7-Way connector. You will need # 37185, some wire (more on that later), a brake controller, and a brake controller wiring harness.

The 37185 will plug into the 4-Way. Then you will ground the white wire to the frame. That will leave a blue wire, black wire, and purple wire. The purple wire is for reverse lights so if the trailer does not have them you will not have to tap that purple wire into a reverse light on the vehicle.

The black wire is for a 12 volt hot lead. If the trailer doesn't have anything on it that requires a 12 volt circuit you don't have to use this wire. Otherwise it will connect to the positive battery terminal via a 40 amp circuit breaker # PK54540.

The blue wire is going to have to be manually run to the brake controller. Basically, you will remove the blue wire from the end of harness # 22292 that plugs into the vehicle and attach it to the wire you run manually. What I recommend is to wire both the black wire hot lead mentioned earlier and the blue wire for the brake controller using duplex wire # 10-2-1 sold by the foot. I recommend about 25 feet of this wire.

Then all you will need is the brake controller. I recommend the P2 # 90885 because it is easy to set up and use and it is reliable. I have included some links that will help with this installation. Not all of the parts of these links pertain to your vehicle so just follow the parts that are relevant to your installation.

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