Hello all. Still new to this diesel forum but I have a few questions. I bought an 03 F-350 back in February and the thing has run great since purchase. But I'll be toeing with it finally,and it seems as though the previous owner cut out the electronic brake control wiring harness. I don't currently own a repair manual for this, so I figured I'd check if the interweb experts have any info. Anybody have any wiring schematics for this particular system? Again, its an 03 with the 6.0 4wd dual rear wheels. Any input is appreciated.

 

2003 - o4 didn't have the integrated trailer brake controllers, that started in 2005. So, you need to buy a TBC and wire it up according to instructions. Probably best to go name brand amd hopefully someone will come along with good recommendations.

 

Where are the wires cut?Look under the dash by the steering colum and see if the cut wires are plugged into a factory connector.If they are you just need a TBC and a Ford adapter.This is what I used.Tekonsha Prodigy P2 #90885 and adapter #3035-P. I got these from etrailer.com. Mark

 

X2 on the Prodigy controller.

There is no integrated Ford controller on the 03. The lead should be under the dash on the right hand side of the steering column. You can get the pin outs of the connector on the rear of the truck from any trailer site. Check that everything is functioning properly before you hook up. Good luck.

 

Mine is an 03. If it came from the factory with a hitch and the 7 pin plug it will have the harness under the dash that you just plug the adapter into and then plug in the TBC. Mark

 

let me be a little more specific. The vehicle did in fact come with the factory wire harness to hook up an electronic brake controller. I'm not referring to an electronic module that came factory. It looks as though the previous owner cut the wires just above the left kick plate, and also there were four wires cut in the engine compartment near the brake booster and master cylinder by the firewall. Im only asking if you guys have a schematic for this that runs from the electronic controller harness plug, p260h/g or plug 14a348 back to the trailer plug. thanks for the replies guys.

 

The 4 wires that look cut in the engine bay are like that from the factory. They're wired to the dash area just so you have an easy time adding accessories. Look up "upfitter switches". One thing they're commonly used for is the high idle mod. The switches might not have been available from the factory on 03-04, but the wires are there from what I read around here,and you can add the switches and relays.
https://www.ford-trucks.com/forums/4...-switches.html

 

The tekonsha p3 is an excellent controller.

 

Yep, mattdoc is correct, don't confuse the uplifter switch wires with the controller wires. Totally different animals.
As others above have also indicated, you need to get up under the pass side of the steering wheel, almost under the radio to find a female plug. That's where you need to connect the adapter harness and controller for braking.

 

I'll try and post some pictures for you guys a little later to show you exactly what im talking about. You all could very well be right in saying those wires are for the uplifter switches, but what they look like are the exact same size and color as the previous fords ive owned with the factory harness in it for TBC. I have looked under the dash for the plug and i havent seen one. ive had the radio out several times before and did not see a plug that fit the dimensions. as i recall, its a six plug connector with white, red, black, and blue wires, correct? thanks for the help guys.

 

On the 03, those wires are not specifically for upfitters. They are just pass through wires.
If I remember correctly, the trailer brake wiring looks similar to the pass through wiring.

 

yes, they look almost identical to the trailer wiring harness. im gonna ring em out later today when i get off post to see if the wires in the engine compartment read to the cut wires in the cab.

 

Isn't the trailer brake controller harness clipped to the back of the filler panel at the bottom of the dash where the controller would be, or is that just later year models?

 

03 and 04 models come with a female, four wire connector that is just about under the radio. This connector is made for a electronic trailer controller to plug in. If you buy a controller made for the 03 ford, some of them come with the male connector that fits perfectly into this four wire female connector.

So, it doesn't make sense for the previous owner to cut any wiring to remove his brake controller. It should have just unplugged. If he did cut the wiring, he cut the wire between his controller and this female plug. Cutting any other wires to remove his brake controller is not necessary and makes no sense.

Again, it is on the drivers side but just about under the radio. I bought a Hayes Endeavor Inertial controller and it came with a plug that plugged right into this plug. I'm happy with the controller. Most nice controllers have an option to purchase the harness that just plugs into the female connector ford placed there.

05 and up can come with the controller, but I suspect they also come with this female connector too.

Edit:

It just hit that the previous owner could have plices into those 4 wires before they reached that female plug. If so, that would have been really stupid, and you may have for wires hanging there almost below the radio.

If I recall correctly, the wire colors are the same as those listed on any electronic controller you can buy.

 

This video might help.Trailer Brake Controller Installation - 2003 Ford F-250 Video | etrailer.com