I am working on a project and don't have 12vdc on the 7 pin plug. I looked in the manual and the relay and fuse appear to be installed. I didn't get a relay and fuse like on my past F150's. I did get the pigtail for the brake controller. Anyone have any ideas before I go back to the dealer?

 

You probably know this, but the ignition has to be ON for 12V to be delivered to the trailer battery circuit. If the relay and fuse are installed, I can't think of any other reason you wouldn't have 12V there.

- Jack

 

My 2014 didn't come with the relay or fuse, but those items came with my OEM integrated brake controller I added.

I highly recommend going integrated route over aftermarket stand alone units. Simple plug and play (plus programming) as well as true variable brake assist based on how much brake pedal you're pushing. Seamless operation.

 

I'm seeing the same thing on my 2015 F-150 4x4 SuperCrew King Ranch truck.

I found out just before leaving on a trip this last weekend. The trailer tongue jack wasn't working so I started troubleshooting and, sure enough, there was no 12VDC coming out of the trailer connector with the engine running or not. The first thing I did was to grab the owner's manual and look for the fuse and/or relay that controls that part of the circuit, but there is nothing listed. I looked through a .PDF of my previous 2102 F-150 and it was in that one, but there was nothing in the new manual at all regarding a trailer tow battery-charging circuit. I even downloaded a newer version of the 2015's manual, but nothing had changed in the fuse section.

This was on Saturday, the fourth, so there were no service people working at any of the dealerships, so I was on my own. I figured that I could find something online, but no such luck for anything on the 2015's. Next, I figured I'd give Ford Customer Service a ring to see what they could tell me. They don't have any "technical" information available, so they advised me to contact my dealer's service department, which I explained that I couldn't do due to the holiday. So much for help from Ford. In the meantime, we loaded up the trailer and left on Sunday without the charge circuit.

I have now tried over a dozen different dealers all over the USA to try and find out what the fuse and relay number should be, but they are all either clueless or won't look it up in their service manuals because Ford doesn't pay them to do that. They could only suggest they I make an appointment, bring in the vehicle, and they will troubleshoot it for me. That way they get reimbursed, but I certainly get nothing for my time, trouble, and frustration!

I suspect that the factory either forgot to install the additional fuse and relay for the circuit or they forgot to throw the parts into the glove box for us to install. Either way, it's a stupid mistake that shouldn't have happened and then for them to have excluded the info from the manual only compounds the issue. <SIGH>

Hopefully, I can get this all sorted out when we get back home.

 

Can someone explain to me why Ford doesn't install this stuff on a vehicle specifically purchased with a "Tow Package" in the first place?

 

Are you SURE the owner's manual doesn't tell you where the trailer battery charging fuse and relay are located in the Power Distribution Box? My owner's manual for my 2014 truck does. But, the fuse and relay were both in a plastic bag in the glove compartment, so I had to install them myself. Once installed, power was present at the plug.

In my truck, relay #9 is the Trailer Tow Battery Charger, and fuse #21 is the Trailer Tow Battery Charge Relay Power. I'm giving you the names in the hope that they have not changed. And, my truck has two fuse/relay panels - one in the engine compartment and one in the cab on the right side.

Why the factory does not install these items is a mystery to me. I had to install the fuse for that circuit in my old 2005 King Ranch too.

- Jack

 

I have had to install the relay and fuse in every Ford truck I've owned (I'm on my 4th). On the 2011 there was a fuse panel above the radiator right behind the hood latch that had an empty spot for a small relay and large fuse. I'm not sure if this has changed for the 2015s. I'm not sure why they do this but there has to be a good reason since the include all the parts. From what I remember the manual didn't specifically say where and how to install the parts. What I did was look at the fuse/relay charts and find the ones for the trailer power then compare it to the parts in the glove box. Since they were the right parts and weren't installed I knew that had to be them.

 

The 2015s are smart( or annoying, your choice). It won't power up the 12V until you are actually connected to a trailer and do a setup (name the trailer) in the trailer menu on the info screen.

Page 110 in the manual. Set it up and you should have 12V when a trailer is actually connected.

 

I'm wanting to use the 12v without having a trailer connected. I took it to the dealer and they did test and said it's showing an open circuit. Will have to take it to them or I may just run a line from the battery.

 

I am just taking this thread back to the top instead of starting a new one.

I am also having this same problem on my new 2016; NO 12v power at the 7 pin trailer plug. I have a dual port 12 volt power adapter that plugs in the 7 pin plug to run 12v accessories like a small air compressor etc. (like this https://www.amazon.ca/Reese-Towpower...204460_TE_item)

I just tried it yesterday for the first time and it had no power. I bench tested the adapter and it is working.
When looking at the plug at the back of the truck, the negative (-) is at the 1 oclock postion and postive (+) is at the 7 oclock.
I put a multi meter on those trailer plug pins with the truck running and no power. On the dash computer I entered that I had my trailer hooked up and still no 12v at those two pins. The turn signals (pins at 9 oclock and 3 oclock respectively) and running lights (pin at 5 oclock) HAS 12V POWER.

I just happened to have an appointment today at the dealership for oil change and had them check this. The tech reprogrammed 2 things on the on board computer and said it was working now. Well, before leaving the lot I plugged in my little 12v adapter and NO POWER!

The tech came out with a shop made board they have for checking trailer wiring. With the truck running, trailer connected on the dash and even added a "new" trailer still NO POWER! He plugged in the shop computer and could not see what the problem is. So the dealership it stumped. They will be "calling Detroit" to see if they have a solution.

So, turn signals work, running lights work, brakes work but NOT 12v dc. So, if you have a camper, while driving you will not have power for your fridge or interior camper lights, charging camper battery etc.
As far as having a 12 volt power at the back of the truck, I think I will just run a wire/fuse right from the battery and mount it in the rear of the box.

So, this is something you should check before you head out on your summer camping trips.

 

^^^^UPDATE:
So I had my truck at the dealer today and they figured it out....with not much help from Ford head office actually.
To have 12v power at the 7 pin plug you have to have:
1) truck running
2) plug in trailer or power adapter etc
3) put truck IN GEAR...now you have 12v power
4) you can put the truck back into park, leave it running and still have 12v power to run the camper or 12 volt accessories etc
You do not need to have a designated trailer programmed on the dash computer.


Hope this helps

 

Thanks TonyMo

 

Wow, that's not exactly what I would have guessed, but great information! Thanks for sharing with us too!

I can just see this issue causing all sorts of problems down the road when just about anybody goes to work on an F150 trailer plug / wiring issue. I wonder which genius on the Ford legal staff came up with this idea?

 

Tony,... that routine doesn't give me 12v,...... I've been trying to find an answer to this very same problem for over three months,... towed my trailer for 4 months without knowing this problem existed, because all trailer lights and elect. brake work, .... I bought the same gadget you mentioned, a two socket power adapter to have 12v at the back of my truck for a small air pump,.... it doesn't work on my 2015 F150, but does on my 2002 F150,...... even asked the dealer about this when I went for my 1st oil change, but I made the mistake of saying that all my trailer lights work,.....they didn't know, but used that opportunity to claim the 7pin socket must be good and there is a problem with my little gadget,..... I even have a 7 pin tester that shows that something is not right with the 7 pin socket and the 12v light doesn't light on the tester,....I searched other sites and have seen answers like "you have to name a trailer", "there is a relay and fuse that has to be added", and also "the socket is a smart socket and the computer will recognize a trailer when attached",...... the last one may be true, but there is no way to prove it, if when you unplug your trailer the 12v is gone,.... I was really hoping you had the answer but your steps didn't give me 12v either,..... is there anyone else in this forum that has used your method and can report yea or nea,..... any further wisdom on this issue would be greatly appreciated,..... I'd certainly be pulling my hair out over this, if I wasn't already bald...........I guess it could be a smart socket and does receive 12v when (and only when) a trailer is connected, but that will mean it isn't going to power the gadget.........anyway...... HELP......

 

Fella 10 and Tony, this fix did not work for me either.