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Brake Controller Installation-2003 Ford Expedition


Can you send me the wiring diagram or instructions for a 2003 Ford Expedition 2x4.


Expert Reply:

I don't have a vehicle specific wiring diagram for you, but I'd be happy to walk you through the process.

The actual installation will depend on whether or not your Expedition is equipped with a trailer connector and if so, whether it's factory or aftermarket. There are a few different possible scenarios.

1) Your vehicle has the factory 7-way trailer connector on the back bumper. If this is the case, you'll have a plug and play installation. You'll need the # 3035-P brake controller adapter harness as well as the Draw-Tite Activator brake controller you had looked at. The brake controller would mount to the underside of the dash, within easy reach of the driver typically to the right of the steering column so you don't bump your knee into it when entering and exiting the vehicle. The harness would plug into the gray connector just to the right of the OBD port under the steering wheel.

2) Your vehicle has the factory 4-pin trailer connector. All would be the same as above, except you'll also need the # 37185 and a couple of feet of # 10-2-1 jacketed 2 conductor wire. Plug the # 37185 into the existing 4-pin trailer connector, then trace the wire from the 4 pin to where it plugs into a larger connector on the drivers side frame rail. On the side of that connector closest to the front of the vehicle, peel back the jacketing of the cable and locate the orange (or red) and the blue wire. cut those wires, and attach the WHITE wire in the length of 10-2-1 cable to the BLUE wire in the vehicle harness. attach the black wire from the 10-2-1 to the red or orange wire and run the cable back to the # 37185 adapter. In addition to the wires on that adapter that plugged into the factory 4-pin, there are 4 additional wires. Ground the white wire with the ring terminal to the vehicle frame. Attach the BLUE wire from the adapter to the WHITE wire in the 10-2-1 jacketed cable. Attach the BLACK wire from the jacketed cable to the BLACK wire on the 37185 adapter. The purple wire from the adapter is typically used for a reverse light circuit but if it's not needed, you can just coil it up out of the way.

3) If you have an aftermarket 4-pin, look for the gray brake controller connector under the steering wheel. If it's there, you'll complete the install as described above, but there won't be anything plugged into the connector on the frame rail. You'll just cut the wires and tap into them as described above. If you do NOT find the gray plug, you'll need the # ETBC7 install kit which would install as described in the article I've linked for you.

If you have no trailer connector at all, you'll need the # ETBC7 (see linked article) as well as a 4 pin harness, part # C55344. The harness would install by plugging inline with the connection between each taillight assembly and the wiring harnesses feeding them.

I have linked some brake controller installation articles that I hope you'll find helpful.

expert reply by:
Mike L

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