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How To Activate 12V Trailer Charge Circuit On 2019 Ford Super Duty With Factory 7-Way  


I have installed the 30 amp fuse to the number 27 spot for charging trailer battery but am not getting any power to the plug.And I have a factory installed brake control inside the cab and my truck is a 2019 F350 super duty


Expert Reply:

If you have already added the fuse and the trailer charge circuit is not activated in the 2019 Ford F-350 Super Duty with factory integrated brake controller, then you want to make sure the trailer is connected and you press the brake according to a Ford Service Bulletin on their factory integrated brake control with trailer module 12V charging system.

There may also be a dash setting to activate the tow/haul mode on the 7-way before the 12V output is activated.

expert reply by:
Heather A

Mike M.


I also am having issue's with the charging system in my 2019 F350. Replaced the fuse #27 that wasn't blown and it still did not work. I have power to the fuse. I have replaced fuse#65 it was blown. This also didn't fix the problem. Fuse #42 a 40 amp fuse could be the issue. But everything else with the 5th wheel I pull is working. Also I do not find a setting that you have to turn on, to get the battery to charge in your trailer.

Etrailer Expert

Chris R.


Newer Ford trucks (including your 2019 F-350) require that a trailer is hooked up and the brake pedal is depressed before the 12V circuit becomes active. So try connecting the trailer and tapping on the brake pedal, then test the 12V pin on the 7-way to see if you get power.

James B.


What happens if you are trying to hook up your truck camper.

Etrailer Expert

Chris R.


The process would be the same since the truck camper will still be plugging into the factory trailer harness when attached.

Tom I.


I have a 2020 F 150 and mine isn't charging also. Can you tell me what pins I check?

Etrailer Expert

Chris R.


The 12V pin on the 7-Way is the one located in the 1 o'clock position. On your 2020 F-150 there's a 25 amp fuse located in the # 30 spot inside the under-hood fuse box that's in charge of this circuit. Check this fuse to make sure it's present and in good condition.



I too have a new 2020 f350 with an accessory pin that won't activate. even after selecting a trailer and depressing the brake and confirming that a trailer is detected there's no accessory voltage.. I may just have it wired to an upfitter switch and just avoid the whole mess

Etrailer Expert

Jon G.


You could go that route if you wanted to. The only other thing I can think of doing (if you've verified it has the fuse and no power to that specific pin) is to physically trace that wire as much as you can to see if there are any places that have breaks or any damage.

Ronald S.


@Brian They key fob must be in vehicle and doors closed, for my 12v trailer jack to get power. So I can lower trailer tongue onto ball. We almost did not make it to work. trying to figure this out. this is not a desired feature, at all. :(

Tom E.


I have a 2021 F250, it only charges my slide in camper in tow haul mode. It is a light camper and I don't always use that mode, so I had a few dead battery moments before figuring it out.

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