I just bought a 2000 Excursion limited v10 4x4. I'm going camping this weekend so trying to install my brake controller. I foud the plug but noticed these wires dangling. I can't see the back of the harness. I'm afraid the PO may have cut them to install a universal harness. Does anyone recognize them? I don't want to buy a ford specific harness if the wiring has been cut.

 

One easy way to tell is to plug in the brake controller and see if it works.

Another way is to follow the wires from the brake controller plug and see where they go. Also follow the blunt cut wires to see where they go.

Ford originally left some blunt cut wires under the dash for pass through wires used to connect to upfitter switches or for customer access to make it easy to connect a circuit through the firewall without running extra wires.

Also, this is the F150 section, you will get more and better responses in the Excursion section or Super Duty .

 

Thanks good advice about the pass through wires. That's reassuring. I wasn't sure why there would be unattached wires hanging there.

Also, good advice about posting in the appropriate section... . Sorry newb mistake.

I'll take another look and see what i can find. Good news is the Ex handles my pop up fine without trailer brakes.

 

It would always be better with trailer brakes.
Some of the big chain auto parts stores stock the Ford trailer brake controller pigtail. It is a simple matter to splice it to your existing trailer brake controller.
The vehicle side of the trailer brake controller wiring under the dash will not always necessarily be the same color as the wiring color on the standard trailer brake controller harness. This pic is from a 2001 E350 Ford van. As you can see, the wire color is not the usual red white black blue of a typical trailer brake controller harness. The 5th wire on this connector is dash illumination for a TBC that supports that function.
Make sure your fuse box is correctly populated with all the necessary relays and fuses required to operate the trailer brake controller circuit.



On the pass through wires, they are originally not connected at either end. There was originally a white tag on the harness near where they split off the main harness that identifies them as "customer access". On my 1999 F250 they came out under the hood on the firewall just to the outside of the master cylinder. And after 18 years the tag was still there and legible. I used one for adding driving lights since my truck was not originally equipped with them. Driving lights were a dealer option in 1999 for Super Duty trucks.