2019 F250 will not charge trailer battery

**Wicked ace** · 06-18-2020, 03:05 PM

Originally Posted by Riceball1

OK so here is what I found out. I took my truck in for some warranty work and have them fix my charging problem also. They tried to charge me 367.00 Diagnostic fee only to tell me the fuse was missing from slot 65. The book says it controls Trailer Tow Lighting Module. I do not understand but they say this activates the brake controller to turn on power to charging circuit. We had a long discussion about what I paid for trailering pkg and camper Pkg and not have this work. We settled on 50.00 i will be going to hook up trailer tomorrow to make sure it works. SHAME on Ford for not installing this fuse new or labeling it correctly.

You need to call Ford customer service and explain it to them and how your dealer handled you. Also you need to have a talk with the service manager and the dealership manager. That fuse should have been installed with tow package. Things get forgotten during a build but that is why there are warranties. Also you should be getting a survey for you visit to the dealer. Fill it out and reflect accordingly on your experience.

**Steve & Sheryl** · 06-18-2020, 03:21 PM

I'm struggling with this same issue with a 2020 F250. I'm not getting current at the auxiliary pins in the connection, even after pumping the brakes a few times. But once connected, I do have trailer brakes (not just lights). I'm assuming the brakes were powered off the Aux pin? I thought I'd get clever and use the BMV-712 app to see what was happening at the battery while moving. it was showing my normal parasitic loads, so the truck was not charging the battery at all.

Until I saw this thread I assumed that the brake controller was only powering that pin when the the brakes were being applied.

Shouldn't I be able to see a change in the battery load while driving? Has anybody else looked at their Victron while moving. Or better said, has anyone else had their DW look at the Victron app while they were driving?

**Heavy Half Ton** · 06-18-2020, 03:54 PM

I know right?
I was considering the $40 one on Amazon that would probably meet my needs, but then I was thinking “Nah. Sitting outside watching the birds and the bees and my batteries charging on my phone would be pretty cool!” Yolo!

Originally Posted by jkwilson

So you couldn't resist either? Nerd!

**SolarPoweredRV** · 06-18-2020, 06:59 PM

Originally Posted by Riceball1

Does anyone know how to get a F250 to energize the charge circuit on the 7 pin. It looks like it activates automatically when brake controller senses a trailer pugged in but mine does not. Ideas???? Thanks

I had to install a fuse in my 2019 F350's fuse box to activate the 12v power supply on the 7-pin connector.

Additionally, after you connect your trailer, you have to press the brake pedal to let the computer know a trailer is connected and activate the 12v power supply.

**SolarPoweredRV** · 06-18-2020, 07:12 PM

Originally Posted by Wicked ace

You need to call Ford customer service and explain it to them and how your dealer handled you. Also you need to have a talk with the service manager and the dealership manager. That fuse should have been installed with tow package. Things get forgotten during a build but that is why there are warranties. Also you should be getting a survey for you visit to the dealer. Fill it out and reflect accordingly on your experience.

No need to call customer service about the dealer. Ford simply does not install that fuse in their trucks !!! It is not logical as to why, but, that is the way they do it.

$50 was a good compromise from the dealer, it cost me $30 in fuses to get my fuse installed (kept dropping the damn $5 fuses)!!

**SolarPoweredRV** · 06-18-2020, 07:19 PM

Originally Posted by Steve & Sheryl

I'm struggling with this same issue with a 2020 F250. I'm not getting current at the auxiliary pins in the connection, even after pumping the brakes a few times. But once connected, I do have trailer brakes (not just lights). I'm assuming the brakes were powered off the Aux pin? I thought I'd get clever and use the BMV-712 app to see what was happening at the battery while moving. it was showing my normal parasitic loads, so the truck was not charging the battery at all.

Until I saw this thread I assumed that the brake controller was only powering that pin when the the brakes were being applied.

Shouldn't I be able to see a change in the battery load while driving? Has anybody else looked at their Victron while moving. Or better said, has anyone else had their DW look at the Victron app while they were driving?

If your 2020 is like my 2019, your problem is with a missing fuse under your hood. The Aux power for your camper is a separate circuit that does not have a direct connection with your brake controller. Where pressing on the brake comes into play is with the computer inside the truck, the computer has to sense that the brakes are active before the computer enables the Aux Power circuit.

Once you install that fuse, your truck will begin supplying Aux Power to the camper (after the brake has been pressed).

**TheLexx** · 06-18-2020, 09:09 PM

Originally Posted by SolarPoweredRV

If your 2020 is like my 2019, your problem is with a missing fuse under your hood. The Aux power for your camper is a separate circuit that does not have a direct connection with your brake controller. Where pressing on the brake comes into play is with the computer inside the truck, the computer has to sense that the brakes are active before the computer enables the Aux Power circuit.

Once you install that fuse, your truck will begin supplying Aux Power to the camper (after the brake has been pressed).

Whoa, so my 2017 F450 has not been charging my batteries while the truck is running, this entire time? No wonder it seems like the batteries run down so much when I'm in transit!

So let me get this straight. As it comes from the factory, the truck is missing the fuse in slot 65. As a result, when I'm towing, my 7 pin harness is able to control the brake lights/turn signals and brake system of the trailer, but it does NOT recharge the onboard RV batteries. I need to insert the fuse into slot 65 to enable charging of my RV batteries via the 7 point harness. Have I got that right?

**SolarPoweredRV** · 06-18-2020, 10:12 PM

Originally Posted by TheLexx

Whoa, so my 2017 F450 has not been charging my batteries while the truck is running, this entire time? No wonder it seems like the batteries run down so much when I'm in transit!

So let me get this straight. As it comes from the factory, the truck is missing the fuse in slot 65. As a result, when I'm towing, my 7 pin harness is able to control the brake lights/turn signals and brake system of the trailer, but it does NOT recharge the onboard RV batteries. I need to insert the fuse into slot 65 to enable charging of my RV batteries via the 7 point harness. Have I got that right?

This was definitely the situation on my 2019 Super Duty, I can't be certain about the 2017 F450, but I suspect that you do need to install the fuse.

On my 2019 F350, I needed to install the 30amp fuse in position 27 and the fuse was an "M case" fuse, not a typical "Blade type" fuse. If your F450 is like mine, you are going to need a lot of dexterity because that fuse is a PITA to reach and install, (I lost 5 of them before I was able to get it installed).

You can look in your Owners Manual for the fuse position and then check to see if you have the fuse installed, or, take it to your Dealer and they can check the 7-pin connector for you, Note: a normal 7-pin [LED light] tester will not work because of the need for the brake circuit to be connected and actuated before the 12v Aux power is enabled by the computer, the Dealer has a special box they use to test the 7-pin performance.

**TheLexx** · 06-18-2020, 10:30 PM

Originally Posted by SolarPoweredRV

This was definitely the situation on my 2019 Super Duty, I can't be certain about the 2017 F450, but I suspect that you do need to install the fuse.

On my 2019 F350, I needed to install the 30amp fuse in position 27 and the fuse was an "M case" fuse, not a typical "Blade type" fuse. If your F450 is like mine, you are going to need a lot of dexterity because that fuse is a PITA to reach and install, (I lost 5 of them before I was able to get it installed).

You can look in your Owners Manual for the fuse position and then check to see if you have the fuse installed, or, take it to your Dealer and they can check the 7-pin connector for you, Note: a normal 7-pin [LED light] tester will not work because of the need for the brake circuit to be connected and actuated before the 12v Aux power is enabled by the computer, the Dealer has a special box they use to test the 7-pin performance.

OK thank you. I'm going to look for the fuse to see if it's in place. I'll probably have the dealer install the fuse since there are service bulletins and recall notices out on the truck as well. Wow, what a crazy thing! Thanks to all for bringing this to light!!!

**TheLexx** · 06-18-2020, 10:50 PM

Originally Posted by SolarPoweredRV

This was definitely the situation on my 2019 Super Duty, I can't be certain about the 2017 F450, but I suspect that you do need to install the fuse.

On my 2019 F350, I needed to install the 30amp fuse in position 27 and the fuse was an "M case" fuse, not a typical "Blade type" fuse. If your F450 is like mine, you are going to need a lot of dexterity because that fuse is a PITA to reach and install, (I lost 5 of them before I was able to get it installed).

You can look in your Owners Manual for the fuse position and then check to see if you have the fuse installed, or, take it to your Dealer and they can check the 7-pin connector for you, Note: a normal 7-pin [LED light] tester will not work because of the need for the brake circuit to be connected and actuated before the 12v Aux power is enabled by the computer, the Dealer has a special box they use to test the 7-pin performance.

Update:

OK I went over to the Ford Truck Forum and found a couple of threads on this issue. Folks seem to think that in fact, fuse 27 really does not need to be in place. They're saying that if your truck came with the tow package, all you need to do is to step on the brake and that activates the charging circuit.
https://www.ford-trucks.com/forums/1...trailer-2.html

Even better information is to be found on our own GD forum:
https://www.mygrandrv.com/forum/show...g-RV-Batteries

So apparently the word is fuse 27 is NOT required for the circuit to charge the RV batteries. The circuit is energized when you close the door and step on the brake.