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 send current back to charge trailer or 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.