Disabling new Ford's charging circuit

[HeadWest]

Has anyone come up with a way to disable the new Ford trucks trailer battery charging circuit? We just had Lewster work his magic on our International with 700 watts of solar, Victron chargers, larger AGM's, etc. I do not want our 2017 F350 to be putting a pretty much unregulated charge on our new batteries.

The newer Superduty's and apparently the current generation F150's do not have a trailer battery charge relay nor a corresponding fuse installed (they are listed in the manual but nether are present on our truck). However, the have some type of trailer control module and do make the charge circuit live when sensing a trailer which I have verified.

Any suggestions on killing off the charge circuit would be appreciated. I'm very concerned with all the auto sensing stuff going on with a newer vehicle that I could create other problems if I attempt some type of mod on the truck. At the moment, I'm thinking my safest bet is to disconnect the positive charge wire on the ubilical cord at the trailer junction box.

Any thoughts or experience with this would be most appreciated.

[57Vintage]

Did Lewster install a DC - DC converter or its equivalent? That controls any charging to your trailer batteries from the TV (it is adjusted to only supply within the range your batteries' specs require for charging). Mine system is 2 years old (all purchased through AM Solar) and at that time they used an Orion DC-DC converter, not sure what is the replacement now. Victron has updated a lot of the equipment since I purchased.

Suggest you contact Lew and get clarification.

[Crackerman]

Or, just open up the 7 way junction box in the front of your trailer, pull the black wire out of it and cap it. If things are set up properly, you won't have any issues running the jack or breakaway switch with your capacity.this way, you can still pull other trailers with no issues, and no other tow vehicle will damage yours.

[daleyocum]

I ran my 7pin cable’s charge line through a Victron Omicron to charge our batteries but we have Lithium so the TV line needed boosting and regulating. With AGM I doubt the truck would hurt anything but if you are worried, yes, pull the aux charging line.

[Bob662]

Look in your owner's manual. I bet you will find that there is a fuse that, if removed, will disable the charging circuit. It's one of those square, black "box"-looking fuses.

[jimfa440]

Yes, what Crackerman said.

[tbashin]

"Or, just open up the 7 way junction box in the front of your trailer, pull the black wire out of it and cap it"

Or put an on/off switch on the trailer's black wire.

[uncle_bob]

Hi

For whatever reason the fuse locations shown in the owner's manual are incorrect. They have been incorrect for .... errr ... a while now. Just why Ford can't get them right ... no idea.

As mentioned above, better to cap the wire off the 7 pin or put in a DC/DC converter than to mess with the truck.

Bob

[HeadWest]

Thanks all. Yes, I’m going to cap the wire on the 7 pin and leave the truck alone. Seems like my best option and no I don’t have a dc/dc converter.

[pmclemore]

Lewster disconnected the truck's charging capability to my unit - I'd be real surprised if he did not do so for you.

Pat

[uncle_bob]

Hi

The DC/DC converters are a < $100 sort of option. Putting one in isn't much more work than digging in to disconnect the cable.

Bob