Help adding 7 pin to ‘17 XLT 4x4

[Black]

My 17 has the four pin, and that extra wire. If you look at first picture you can still see the writing on the tag.

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Yes all models have the brake controller wire at the 4 pin plug.

He seems to believe the aux. power wire and the reverse lights the last two wires needed for the 7 pin are tucked somewhere behind the drivers wheel well.
Reverse light is not a big deal as that is a simple tap from the tail light but a fused aux. power wire would be a bit more of a pain to run so would be a huge plus if tucked somewhere in the rear.

 

[The6ofus]

mquick5, yep me too. Thanks!

Black, correct! I do not need the reverse wire but it would be ok with me if it’s all there. I definitely need and want the 12v to charge the camper battery.

This is first on my to-do list tomorrow morning, after coffee of course, and I’ll report back here.

 

[The6ofus]

I wish I had better news...

A friend and I spent about two hours trying to locate and trace the wires from the brake controller pigtail towards the back of the vehicle. We were completely unsuccessful finding them coming out of the firewall.

The plug that the dealer said was “without a doubt” for the 7 pin, well it doesn’t appear to be correct. Once I removed the mud flap/splash guard in the drivers rear wheel well I could see a part number on the black thing these wires plugged into. It’s listed as a Fuel Pump Driver Module FL1A-9D370-AA. it does have 7 wires but none that match the colors at the brake controller side of things.

Here’s a better shot of what I thought/was told by dealer/had hoped was the 7 pin wiring.



So, I called it quits and ordered the Curt universal 7 pin and a bracket. My friend had a NIB 7 to 4 pin adapter and I’ll use that for my cargo trailer.

 

[The6ofus]

@theoldwizard1, I did snap a picture of the tag located on the FoMoCo hitch. I have no plans at this time to remotely get close to those towing weights, so whether it’s a 3 or 4 is ok with me.

 

[Black]

I was afraid this would be the outcome. Thanks for taking the time.
Let us know the route you run the power wire.

 

[Yupster Dog]

I wish I had better news...

A friend and I spent about two hours trying to locate and trace the wires from the brake controller pigtail towards the back of the vehicle. We were completely unsuccessful finding them coming out of the firewall.

The plug that the dealer said was “without a doubt” for the 7 pin, well it doesn’t appear to be correct. Once I removed the mud flap/splash guard in the drivers rear wheel well I could see a part number on the black thing these wires plugged into. It’s listed as a Fuel Pump Driver Module FL1A-9D370-AA. it does have 7 wires but none that match the colors at the brake controller side of things.

So, I called it quits and ordered the Curt universal 7 pin and a bracket. My friend had a NIB 7 to 4 pin adapter and I’ll use that for my cargo trailer.

Well that sucks you can't plug and play. good thread for anyone else having same problem.

​

If the aux power wire were tucked some where towards the rear sure would be nice but pretty sure it is not.

This is for a F-150 but it could shine some light on that this elusive aux power wire on the expy too
And here's how they hooked it up.
​

 

[The6ofus]

Thanks for the videos, Yupster Dog.

Reading the diagram for the Curt universal kit I ordered and as long as I truly have power at the OE BC pigtail, all I should have to run is the 12v power, I think. I’m no electrician just a tinkerer.

This is how it will go in my mind...

1) Plug 4 pin from uni harness to OE 4 way

2) Install ground with installed ring at rear of truck

3) Splice OE elec brake wire to uni harness (blue wires) at rear bumper

4) Run single 10 gauge wire (uni harness black) with incl 40 amp relay (and maybe even make it switched power?) to battery for 12v charging

If there are any electrical gurus and this sounds off, please correct me.

Again, that’s if I get positive feedback at the OE controller harness. (Ran out of time today to check) I have all the fuses present in the OE fuse block related to towing, but as goofy as everything else is, I may need to wire as show in the instructions. That requires one more wire and some more splicing. Instructions are located at https://assets.curtmfg.com/masterlibrary/57186/installsheet/CME_57186_INS.pdf

The Curt harness is due to arrive Thursday evening and hoping to install Friday morning to pickup my camper from warranty work at the dealer that afternoon. I’ll post how it goes.

 

[Black]

Granted you already have an after market brake controller but for for like $40 more you could buy the Factory brake controller to fit flush in the dash and buy the 4 and 7 pin connnector that I linked earlier.
The only wires, you would need to run is the Aux. power, and the reverse wire.
You would also have all your gain and controller readouts displayed on your dash.
Would be a far cleaner and easier install for $40 more. Granted you would need to return the Curt harness you ordered.
Heck dependent upon your brake controller could likely sell it and in the end not cost you more.

But I also hate wiring and want as few taps or extra wires ran as possible.

 

[The6ofus]

Thanks Black! I’m short on time now and appreciate it. I agree it would be a cleaner install and less hassle when switching trailers and nice to see the info in the dash.

The short on time bit involves my RV dealer. It’s a long story that I’d rather not muddy this thread with.

 

[Mad Oshea]

UHall will do it in 5 seconds for the price of the connector.