Help adding 7 pin to ‘17 XLT 4x4

[The6ofus]

Hi all! Newbie here that tried searching but couldn’t find an answer to my specific question.

I’m looking for the easiest, least intrusive way to add a 7 pin connection to pull my pop up camper. I’ve already found and rerouted the brake controller wires in the dash. So that tells me that somewhere in the back there must be another plug and play connection, or maybe not? I do have the 4 pin and see one more capped wire next to it. I also located a large, round plug that is connected to something just behind the driver’s side rear wheel. I’ve spoken with and emailed these photos to etrailer and they insist there should be a large round plug at the right rear closer to the bumper. I’m wondering if that is simply a storage location, similar to the brake controller pigtail, for the 7 pin.

I hope someone can clear this up for me soon. Picking the camper up Friday and gotta have that 7 pin. Thanks in advance!

4 pin



Here are 3 sequence shots showing the location of the large round plug.

 

[catmandu]

Interested in the answer as well.

 

[The6ofus]

I should get a chance to dig into it Tuesday morning to test/trace wires. If I learn anything new I’ll be sure to post the results.

 

[Black]

Pretty sure that those of us without the HD tow package only have the trailer brake wire (that capped one next to the 4 pin) and the plug behind the left dash cubby for the factory controller.
If the aux power wire were tucked some where towards the rear sure would be nice but pretty sure it is not.

Did you install the factory brake controller in the dash and activate it and turn your gain display on in the dash with ForScan or going aftermarket for brake controller?

 

[The6ofus]

Thanks Black. I have an aftermarket that I removed from the Explorer I traded in. It’s only a year old and works fine, so I’m sticking with that.

I hear what you are saying. If I have to splice in a universal setup I will. Maybe my logic is flawed, but there are 7 wires in the controller pigtail at the dash. I don’t have the colors in front of me, but they have to go somewhere.

It is odd that this truck has a Class IV hitch, the tow/haul button on the shifter and a 7 wire controller connection at the dash, and fuses in all the right spots for a 7 pin, with just a 4 pin at the back. I do not have the extra oil cooler so I guess that and the 7 pin would’ve made it the HD Tow package.

 

[Black]

Thanks Black. I have an aftermarket that I removed from the Explorer I traded in. It’s only a year old and works fine, so I’m sticking with that.

I hear what you are saying. If I have to splice in a universal setup I will. Maybe my logic is flawed, but there are 7 wires in the controller pigtail at the dash. I don’t have the colors in front of me, but they have to go somewhere.

It is odd that this truck has a Class IV hitch, the tow/haul button on the shifter and a 7 wire controller connection at the dash, and fuses in all the right spots for a 7 pin, with just a 4 pin at the back. I do not have the extra oil cooler so I guess that and the 7 pin would’ve made it the HD Tow package.

Certainly does seem strange but nothing surprises me anymore with car manufacturers.
If you find it do please let us know. I don’t tow anything other than a small trailer for my 4 wheeler and Dr Field and brush mower at the moment so I have not bothered upgrading yet.
Maybe some day I’ll finish my Mustang and will tow it from time to time up to MidAmerica then I’ll get around to it.

The HD tow package also has an different radiator than we do.

 

[The6ofus]

True. I equate it to the halogen headlights with LED “fog” lights. [emoji849]

Ah, good to know on the radiator. There’s a bracket on the front of my radiator that looks like it would hold an extra oil cooler. I’ll post up my findings, no matter what I do or don’t find.

My ‘13 Explorer XLT 4x4 had everything I needed to tow the camper. Oil cooler, Class IV and a 4/7 pin. Oh well! Definitely like everything else about this Expy.

 

[Yupster Dog]

I hear what you are saying. If I have to splice in a universal setup I will. Maybe my logic is flawed, but there are 7 wires in the controller pigtail at the dash. I don’t have the colors in front of me, but they have to go somewhere.

It is odd that this truck has a Class IV hitch, the tow/haul button on the shifter and a 7 wire controller connection at the dash, and fuses in all the right spots for a 7 pin, with just a 4 pin at the back. I do not have the extra oil cooler so I guess that and the 7 pin would’ve made it the HD Tow package.

I had a 02 XLT 2x4 and it had the 4 pin. (no trans cooler) It had (under the dash) the plug for the brake controller. I went to Hitch world at U-Haul and bought both harnesses. I just unplugged the 4 pin and plugged in the 7 pin. Then the harness for the brake controller had what wire was what. I spliced it to the brake controller and plugged it in. the only other thing was fuse and relay under the hood. I did not have to splice 1 wire on truck so I am pretty sure you wouldn't have to on your 17.

 

[The6ofus]

I had a 02 XLT 2x4 and it had the 4 pin. (no trans cooler) It had (under the dash) the plug for the brake controller. I went to Hitch world at U-Haul and bought both harnesses. I just unplugged the 4 pin and plugged in the 7 pin. Then the harness for the brake controller had what wire was what. I spliced it to the brake controller and plugged it in. the only other thing was fuse and relay under the hood. I did not have to splice 1 wire on truck so I am pretty sure you wouldn't have to on your 17.

Good to know! I am wondering if that connector I have in the first post goes to the 4 pin currently but the truck side has all 7 wires. That’s one thing I need to test. I will need to keep my 4 pin for my 5x8 enclosed cargo trailer we use as our “pickup truck bed”, hauling all kinds of stuff occasionally.

 

[Yupster Dog]

I will need to keep my 4 pin for my 5x8 enclosed cargo trailer we use as our “pickup truck bed”, hauling all kinds of stuff occasionally.

There is a adapter 7 pin to 4 pin that plugs right into the 7 pin. I wouldn't keep changing out harnesses. Plus when you change it I would silicone caulk it so its all nice and waterproof.

 

[The6ofus]

There is a adapter 7 pin to 4 pin that plugs right into the 7 pin. I wouldn't keep changing out harnesses. Plus when you change it I would silicone caulk it so its all nice and waterproof.

Good point! I have seen those on etrailer as they were trying to answer my questions.

 

[Black]

Get this wiring kit and you will have the 7 pin and 4 pin. No need for an adapter. I have a 7 to 4 pin adapter for my Z71 and it is just another thing to worry about.
https://www.etrailer.com/Wiring/Curt/C57674.html

I would cut the 4pin connectors off and splice all the wires together as opposed just to the plugging the new Curt 4 pin to factory 4 pin.

I know you are short on time but would be nice if someone with the factory 7 pin would show the harness behind the wheel to see if one could just buy the factory 7 pin harness and plug it in there. Since the Aux power is a fused hot wire they may have terminated it there for safety reasons.
Why they did not just terminate the trailer brake wire there too I have no clue. Also does not explain why they did not run the reverse light along with the trailer brake wire too.

 

[theoldwizard1]

It is odd that this truck has a Class IV hitch, ...

Technically, I think it is a Class III.

The HD tow package also has an different radiator than we do.

Yes ! If you want the HD radiator it is a "drop in" replacement. The auxiliary transmission cooler might take a couple of hoses, tubes, clamps.


My daughter had this done on her '12 Expedition. The place that sold her the trailer actually ran a separate power wire from the battery to the dash and brake controller and then to the 7 pin connector. Clearly not all of the necessary wiring was in place.

 

[The6ofus]

I’ll have to post the hitch details. It reads class 4 as I recall but wouldn’t surprise me with all the other stuff being weird that it’s a 3. The 3 will be sufficient for my 2200# camper.



I’m currently at my local dealer getting a 2nd key made and stopped in the parts department. The gentleman there said the pigtail I’m seeing on the frame rail is “without a doubt” in the storage holder and “is definitely” for the 7 pin. He swears they’ve helped about a dozen other 15-17 Expedition owners with the same question. The service department offered to confirm it for me for the low, low price of $135! [emoji44] I declined for now and will dove into it in the next few days.

 

[CaptOchs]

I wouldn't think a popup would "require" a 7-pin. Most of the older popups are 4-pin. I suppose it's probably to charge the trailer's battery and possibly electric brakes.

Personally, I think if I was in your situation, I'd clip off the 4-pin (they corrode easy anyway) and make my own 7-pin female plug. You're under the weight limit for required brakes; except in the nanny states. http://www.brakebuddy.com/towing-laws.html I've got the 2003 with the 5.4L and I have towed many trailers/boats that are in the 2000-3000# without brakes. The truck's brakes were more than sufficient in braking. If you were towing with a different vehicle that has a max tow of 3000#, that would be a different story.

 

[theoldwizard1]

I wouldn't think a popup would "require" a 7-pin.

I pulled a large pop-up that had brake with my E150 for many years WITHOUT a brake controller. Never an issue.

 

[brhulen]

The first time your trailer sans brakes "comes around" when braking suddenly on a wet or slick road will make you a believer! I know there are many folks who will dispute the necessity of such a useless item and who have pulled thousands of miles with no mishaps but all it takes is once! If nothing else consider the cost of the body repair to your tow vehicle and trailer after your "incident". And of course there's all those pesky litigious drivers who had the audacity to be struck by your trailer or tow vehicle when you lost control. It's true when pulling a lightweight trailer the tow vehicle probably has adequate brakes to stop. Understand though the trailer is connected by a ball and naturally wants to swing to one side or the other under sudden stops or if your trailer fire blows out.

 

[CaptOchs]

I pulled a large pop-up that had brake with my E150 for many years WITHOUT a brake controller. Never an issue.

Exactly. If you just drive reasonable and use common sense I wouldn't worry about it.

 

[The6ofus]

Ah! I love the Internet. I appreciate the input but I will be using a seven pin. Thanks!

 

[mquick5]

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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