trailer battery charging from tow vehicle

[ekonkjack]

While searching for the fuse in the f150 that protects the circuit for the trailer parking lights, I did find it and yep, it was snapped, I find a listing for "Trailer tow battery charger" and it gives me a location 9 and when I find the spot in the fuse/relay box it is vacant. This truck has everything else for towing. Why wouldn't it have this relay? Is it just a matter of popping in the right relay and I'd be able to charge the trailer battery while driving?

[Grumpa]

Yep, had same with my F150 that has tow package. Picked up both fuse & relay at stealer for under $20

[Grumpy]

It is usually in the glove box on FORDS for owner install.

[Iraqvet05]

I owned two new Silverados that had the tow package but did not come with the fuse to energize the trailer charging circuit. If I remember correctly, they didn't even have the wire connected to the power terminal at the fuse box.

Anyway, I just looked at my F250 and found the fuse and relay are not present for the trailer tow battery charge relay either. After some reading on a Ford forum, it seems some newer Fords use a different circuit path to charge the trailer battery and do not require the fuse and relay. A few users posted that in order for the charge circuit to energize, the trailer must be connected and recognized by the truck then the service brake and brake controller must see a signal (depress pedal for a few seconds) before the charge circuit energizes. Looks like I need to hook up my trailer and take some voltage readings at the trailer battery before buying the fuse and relay.

[Grumpy]

Originally Posted by Iraqvet05

I owned two new Silverados that had the tow package but did not come with the fuse to energize the trailer charging circuit. If I remember correctly, they didn't even have the wire connected to the power terminal at the fuse box.

Wonder if it depends on what plant produced them? Both my 2011 and 2018 came already connected and fused.

[Iraqvet05]

Originally Posted by Grumpy

Wonder if it depends on what plant produced them? Both my 2011 and 2018 came already connected and fused.

Could be. Mine were 2003 and 2007 models. Looks like GM did this to the Suburban too... https://www.ifixit.com/Guide/How+to+...Suburban/55434

[Mustang65]

Originally Posted by Grumpy

Wonder if it depends on what plant produced them? Both my 2011 and 2018 came already connected and fused.

My 2012 F150 (Ohio plant, special order) had the relay in the glove box
Don


My Registry

RVing with SOLAR

[suzieshome]

Maybe this explains why my old 2012 never charged the battery. Never worried about it too much because we always had shore power. Have to check out the new truck