7 pin trailer wiring

The first thing you need to do is figure out if your Explorer has a brake controller - because 7-pin usually means trailer brakes and a controller is involved.

Is the trailer plug flat pins or round? The OEM Ford is the flat "RV" type recepticle, commercial trailers use the round pin style.

This is the industry "standard" wiring colors.



This is the OEM Wiring. The CAN/BUS system makes wiring lighting more involved than in the good old days. The Hoppy plug-n-go won't work with the new wiring systems.

I have looked for a controller and it does not have one. It has the towing package but it has the smaller hitch and they are going to put on the bigger hitch for me. I have not even looked at the wiring that close. The parts guy at the Ford dealer here said they did not make a factory plug for a 7 pin for this year model. I think he said they make one for the year above or below or both just not for this year model. I just wonder if they make one for the other year models if it would work on mine. I would just have to add a controller.

hillbily said:

The parts guy at the Ford dealer here said they did not make a factory plug for a 7 pin for this year model.

Click to expand...

Well if they don't make one why would it be in the service manual wiring diagrams. These I posted are straight out of the 2009 Explorer factory service manual. Did you notice the service pigtail part numbers???????

I did not know it was from the manual. Thanks. That tells me he either does not know what he is doing or his book is wrong.

Straight from the 2009 Explorer Wiring Manual.

hillbily said:

I have looked for a controller and it does not have one. It has the towing package but it has the smaller hitch and they are going to put on the bigger hitch for me. I have not even looked at the wiring that close. The parts guy at the Ford dealer here said they did not make a factory plug for a 7 pin for this year model. I think he said they make one for the year above or below or both just not for this year model. I just wonder if they make one for the other year models if it would work on mine. I would just have to add a controller.

Click to expand...

It is very odd that it would have the towing package but has the smaller hitch.
I think the dealer may be a bit confused, I have seen that a lot when I was looking for my 08 vehicle. It may have tow package (in the sense that it has the 1.25" reciever and a 4 pin connector) but this is not same as the heavy duty optional tow package. That one comes with 2" reciever and both 4 pin and 7 pin electrical connector. Usually when we talk about the tow package we mean the heavy duty one as the smaller reciever is standard and not really a package.

I would be very careful what you tow with this one until you find out. You will likely be limited to the 3500 lbs tow rating of the standard explorer. A decent size enclosed trailer that has brakes (usually has when it uses the 7 pin connector) will weigh between 2,000 and 2,500 lbs empty.

In regards to the brake controller, they do not come with the vehicle. They will be pre-wired for a brake controller, but you will have to supply your own. There is a wiring connector underneath the dash under the steering wheel for plugging in a brake controller.

I have the late model 08 Mountaineer with the HD tow package. It came with the 2" reciever, 4 and 7 pole connector and the prewiring for the brake controller.

When you say that something has a towing package, it is implied that it is an additional upgrade package, beyond standard.

The person you are talking to at the dealer does not know what he/she is talking about. They are at a desk with a book or a computer, but no actual knowledge of the product.

Since 2002, all Explorers/Mountaineers come standard with a class II (1¼") receiver, and enough structure and cooling equipment to handle up to 3500 lbs. Regardess of engine or drivetrain, from the factory, if you did not get the HD trailering package option, you are limited to 3500 lbs. This also includes a 4-pin flat harness for trailer lights, which you probably have found by now.

The HD Class III/IV towing package includes an upgraded 2" receiver. I think you also get upgrade engine and transmission cooler (not sure on that part). If you have the V6, you get different axle gearing good for somewhere around 5000 lbs tow rating. If you have the V8 (2002-2005), you get the axle upgrade and somewhere around 7100 lbs. 2006-2010 V8 with tow package gets the 7100 lbs without the axle upgrade, due to the standard 6-speed transmission. The HD package also includes (in spite of the clueless dealer guy) an upgrade to 7-pin connector for lights, trailer brakes, and an aux 12V power line.

So if you have the 1¼" receiver, regardless of your drivetrain, you are limited to 3500 lbs. But it sounds like you have a trailer that you want to tow, that has a 7-pin harness.

1. If this trailer is more than 3500 lbs loaded, then you do not have enough truck for the job. You can't swap out the hitch on this truck since it's welded in. You would have to add a lower-mount hitch and end up with 2 receivers. But that still leaves you with only 3500 lbs towing rating. If you have the V8, you would at least need to add more transmission cooler. If you have the V6, you would also have to upgrade your axles from 3.55 to 3.73 gearing.

2. If this trailer is 3000 lbs or less, then you are probably find to tow this trailer without upgrading the hitch. Class 2 is good for up to 3500 lbs. Just go to etrailer.com or any RV shop, and get the 7-pin connector. You will not use all 7 pins. Just cut off the existing 4-flat connector, and wire into the proper pins in the 7-pin socket.

3. If this trailer is 3000-3500 lbs, it's a gray area. You'd need to check your combined vehicle weights against the GCVWR (check your manual, or the Ford Towing Guide online).

Thanks for the help guys. you both are right I figure. The vehicle came with the smaller reciever and 4 pin. I have added the bigger reciever and will add the 7 pin connector. The trailer is a 7x14 and with my harley in it it weighs less than 3500 lbs. I figure I will be safe there until I get pulling up some steep hills. I have talked to the guys at the dealer and there are checking on getting me a factory wiring harness for the 7 pin if they can.

I guess my next question is everything I need to hook up a brake controller under the dash? I am refering to the plug in the harness and any relays or what not. Any Ideas there?

Actually, from what you describe as needing to tow, I see no need for a 7 pin harness. Do you already have the trailer for your HAWG? what connection is on the trailer, and does it have electric brakes on the axle(s)
If you have brakes on trailer, you will need brake controller and most likely a round 6wire harness.

He already said in the OP that he needs a 7-pin setup, and his last post said he has a 7x14 trailer. He needs the standard 7-pin Bargman setup.

Check to see if you have the plug underneath for the brake controller. It's a connector with capacity for 6 wires, although it will only have 4 wires (if it's there at all). Without the tow package, you probably do not have it.

In that case, wiring for brakes is a bit of work, but it's doable. I did it on our minivan (including a 12V aux charge line).

Go to etrailer.com and search for the proper kit. Or have an RV dealer set you up. They will do as good or better than the Ford dealer.

Thanks for the help I have the dealer ship checking about getting a factory 7 pin setup. I will also go check at etrailer to see what they have. I appreciate all the advice.

14' contruction trailer

hillbily said:

Thanks for the help I have the dealer ship checking about getting a factory 7 pin setup. I will also go check at etrailer to see what they have. I appreciate all the advice.

Click to expand...

I've got the same thing going on for my 2006 Mountaineer, I just installed the Class III/IV hitch, Noticed that the blue trailer brake wire is already running to the back beside the 4 pin connector. Did you find a 7 pin harness from the dealer?

Also does anyone know if I need to install an extra tranny cooler? I have the 2006 AWD with the V8.

Thanks Kabel

No I did not find the harness from the dealer. I just did the wireing myself with what I could get from some of the wiring stores. I did get a ford number for the wiring harness from a guy here but ford told me that number did not show up. My explorer has a V6 and I have not added a trans cooler. I am not hauling that much of a load either. Good Luck.

cableporter said:

I've got the same thing going on for my 2006 Mountaineer, I just installed the Class III/IV hitch, Noticed that the blue trailer brake wire is already running to the back beside the 4 pin connector. Did you find a 7 pin harness from the dealer?

Also does anyone know if I need to install an extra tranny cooler? I have the 2006 AWD with the V8.

Thanks Kabel

Click to expand...

Your '06 V8 has the 6-speed transmission, which would not have received any axle ratio changes if you had the towing package. So IMO, you need the hitch upgrade, the 7-pin connector conversion, and possibly some cooling upgrades.

Here is the 2006 Ford Towing Guide. On page 14, it's not clear if the 53G package upgraded any cooling or not. It does not make sense that the base shows an "X" under trans cooling, then the optional package shows "Std". I would consult your dealer and ask them exactly what was included in the 53G package.

I highly recommend getting a ScanGaugeII to monitor trans temperature and other items if you intend to tow more than 3500 lbs very often. It's also a scan tool for pulling/clearing trouble codes.

You can go to "etrailer.com" for the connectors that you need, also the Class IV hitch that bolts directly. My 2008 Explorer 4X4 came with the additional trans cooler from the factory. It does have an extra 12V constant power wire as well. You simply have to wire for the brake control, which comes with directions. The class IV is a 2inch reciever and took me all of 20 minutes to bolt in place. It also clears the spare tire, so simply remove it to put the hitch on, then put the tire right back in place when done. Your extra brake wires can be run down the side of the frame, for protection, and tied in place with wireties. Total job time is less than an hour, an I'm an old fart. LOL Good Luck

hey I know this is an old post but I was wondering ( as I am getting a 2002 sport trac on the road and ready tow ) with the need or the extra transmission cooler needed for towing would I be able to use the front ac portion of an old rad as a cooler ( yes I know it would take a lot more fluid but would it work say an inch or so in front of my rad and would it help overall plus looking at putting in a inline type filter?

But anyway back to the trailer wiring I would like to do the 7 pin connector and upgrading to the class III/IV 2" receiver ( just want more of the strength and the option for electric brakes if needed short term only )

I am new to fords and I am having problems finding any info or diagrams or videos showing what I need and where to look for a factory connector if any for the 7 pin also how to wire what where.

any help would be great.

Thanks

Hi explorer fans, I need some advice on my 7 pin connector and brake control wiring for my 2007 explorer. It came non tow package, ie small hitch and 4 pin flat. I ordered up the Etrailer, ETBC7 and a primus iq brake controller. I looking for info on how to hit the "brake control" signal wire. I see a white connector under my dash set up for 6 pins, but only currently having 4 pins in it now. Etrailer says "don't buy the ford specific wire harness for brake controller". They indicate "even if the connector is present under the dash, since it only came with 4 pin flat, the brake control connector won't be hooked up". I'd rather take a $15 chance not to hack up the factory wiring and buy the harness, if this connector is not hooked up then what wires and I to hit under the dash? It's got to be one if them. Pics of the connector under my dash below. Any advice would be appreciated.

Hello you hoo?