Late Model Ford F350 Can't charge the truck camper battery

dkiel

New member
Our new Ford F350 won't charge the truck camper battery! Has anyone heard of any problems with late model Ford trucks not sending power back through the trailer hitch’s seven-pin connector to charge the truck camper’s house battery? I’m pretty sure it isn’t my Truck Camper, but is something in the logic Ford uses to decide to set the relay to send current back to charge TC house batteries. I’m also sure it isn’t the common problem most trucks have of too small of a wire to get enough current to the TC battery. NO current is making it back to the the trailer hitch 7-pin connector. Also, the electric brake controller and truck’s logic display on the dash panel’s display indicate nothing is connected to the trailer hitch 7-pin connector.

Here is some geeky technical trouble-shooting background:
-We got a new 2017 Ford F350 for our older truck camper. According to our Victron battery monitor, our old Tundra could get about 1- 2 amps back to the TC house battery. Our new Ford couldn’t get any current from day one.

-I’m pretty sure the problem isn’t with the TC. I started trouble shooting the TC wiring, and determined that the TC’s house batteries voltage could be measured from the TC’s pigtail connecter when it was unplugged from the trailer hitch’s 7-pin connector. The voltage was within 0.05 volts of the battery voltage measured at the battery posts and by the Victron battery monitor. So, I’m pretty sure my TC 12 volt charging wiring is fine from the trailer hitch to the battery.

-Then I checked for a voltage on trailer hitch 7-pin connecters’ 1 and 7 o’clock positions (as well as all the others). There was no voltage detected for battery charging but all the running lights etc. worked fine. Then I checked the fuse for the trailer-charging relay and found it missing so replaced it. There was still no current going back to the pigtail.

-I took the truck and camper to the dealer. It turns out, not only was the fuse missing, but also the relay and its wiring harness, and fuse and relay socket for trailer charging. They ordered the parts and were about to replace them when they contacted Ford again and found out the design was changed, but not yet recorded in the tech manuals. Ford now has a new circuit system that won’t close the relay to send current back to the 7-pin connecter unless the pigtail is plugged in and “detected”. My truck was assembled in July of 2017 and we bought it in December.

-But when my pig tail is plugged in, it won’t trigger the logic to send current back to the 7-pin connecter. Nor does the truck’s integrated brake controller recognize that there is something plugged into the trailer hitch 7-pin connector.
 

gopherslayer

New member
We just bought 4 SDs at work. I’ll have to check them out this weekend when I go back to work. I really like the drivetrain of these trucks but the electrical leaves a lot to be desired. Same goes for the half tons. They are a pain to troubleshoot because of the abuse we put them through. After 3 years you may as well take them to the scrapyard because of the abuse.
 

TexasSixSeven

Observer
It seems to be an issue with a few of these trucks that they sometimes don’t register a trailer when connected, and do when disconnected. I’d assume the same could be said for the TC.
 

TexasSixSeven

Observer
Mine has been flawless for me. But I have seen a few issues on the 17+ pages. Mines a 17’ F-350 as well. Post some pics when you get a chance.
 

Buliwyf

Viking with a Hammer
Is the trailer LED? You might have to add load.

Check the fuses under the hod and the kick panel.

Also check the "plugs of death" near the spare tire. Use a good dielectric grease to seal them back up.
 
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1stDeuce

Explorer
The integrated brake controller is looking for resistance over the trailer brake circuit to "detect" trailer brakes, not just to have any connector plugged in... Your truck camper connector isn't populating that circuit, since it doesn't have trailer brakes...

As for the "smart" logic, I should think it would work... Ford has had the charge or aux circuit in the trailer connector powered by a relay that required the engine to be on for years... Whatever their new logic is, it kinda sounds like it's also looking for resistance (or possibly voltage) at that circuit before it is turned it on. Keeps it from corroding in the long run, since it's only hot when needed. (Having 12v to the pin all the time will quickly corrode it if exposed to salt, humidity, etc...).

Once you have all the parts installed to make it work (Go Ford!) you may find that it charges like it's supposed to. If not, check the camper to see if there's some sort of isolator installed in the charge circuit. If there is, you'll probably need to remove the isolator, since it makes the circuit look like nothing is connected. An isolator isn't necessary with Ford's logic anyway, since the truck will only be connected when it's running. When you shut the truck off, it will automatically disconnect the camper.

Good Luck!
 
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Buliwyf

Viking with a Hammer
IIRC, you have to stomp on the brake to wake the plug up, as well. If I park with the truck running, and plug the trailer in, I don't think it lights up until I jump in and hit the brakes.

I'm renting a trailer (with no brakes) this weekend. I'll look into it.
 

Buliwyf

Viking with a Hammer
There was a bad batch of cooler lines a looooong time ago.

You can plug the trailer in with the truck running. In fact that's the preferred way to plug and unplug so you don't get the trailer warning fault. Something is wrong if you're popping fuses. There's nothing on the trucks side that can wipe out a fuse. Only the load can do that. (trailer issue) We have an entire fleet of Fords that only start once a day, and run all day. So we all hook up hot.
 

Tex68w

Beach Bum
Another neat feature with the 17 fords, try plugging in the trailer with the truck on..........you will blow the fuse. They are also picky as to what trailers the computers will "allow" the lights to work on. We have 8 SDs at work, what an overcomplicated mess of a truck.

I won't even start on the transmission cooler line leaks

That's not just on the 2017+ trucks, it happened to me a few times on my 2016 as well.
 

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