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I have a 2017 F250 Diesel. I bought a motorcycle trailer and the interior lights dont work. I took the truck into the trailer dealer, and they stated the line for this on my truck isnt hot. They stated it was fuse 27. I looked and it seems like there is a fuse in position 27 but its a little difficult to get to. Is this the right fuse or should I look elsewhere?
 

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Check and see if you have a module also. (Not all trucks do, I'm told.) We've had an issue with ours as we got a trailer fault which threw codes which, in turn, disabled trailer battery charging. In our case, not only does the truck have to recognize a trailer, but also requires that brakes be applied before battery charging occurs (in addition to no codes). Probably not your issue, but it's also not as simple as it use to be, either. Here's the info I was given: https://ford.oemdtc.com/2482/trailer-charging-system-operation-2017-ford-f-super-duty

Good luck! David
 

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The truck needs to be running to feed that pin, too.
 

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In our case, not only does the truck have to recognize a trailer, but also requires that brakes be applied before battery charging occurs (in addition to no codes).
That makes absolutely no sense. Why should it be required that you be stopped with the brakes applied to charge a trailer battery? It makes more sense to charge while running down the road, not when you're sitting getting zero mpg. :scratchhead:
 

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That makes absolutely no sense. Why should it be required that you be stopped with the brakes applied to charge a trailer battery? It makes more sense to charge while running down the road, not when you're sitting getting zero mpg. :scratchhead:
I agree, that makes no sense.
 

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I agree, that makes no sense.
Here's the actual document quote, "For trailer charging to operate, the TRM must detect a trailer is connected and a brake pedal input before charging will be present at the trailer connector."

David
 

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Check all the trailer related fuses. I had the same issue, i added the extra fuse and played with the brake, the lights still wouldnt work. I stumbled on a blown fuse for the tail/turn lights #72 which worked fine but after i replaced the fuse the aux lights in the trailer worked made no sense but everything works now
 

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I have to agree with davydee. Had trouble with charging until I found about the right procedure. I now make the trailer connection and then step on the brake. No troubles with charging anymore.

Dave
 

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I've also found that doing a brake test using the brake controller itself does not set the power on - it has to be the brake pedal. Not sure why and the diesel tech I spoke with in Limon Co (not a Ford Dealer - a Heavy Duty Truck repair shop) had never heard of such a thing (BTW I was referred to him by a fellow Ford owner who lives in Limon. I spoke with him at the local gas station while fueling the beast. Regardless, he told me the guy was super with diesels and worked on all makes and sizes of diesels.). In any case, this step on the brake pedal to activate your trailer charge circuit is definitely not publicized by Ford, nor well know either. Thanks for getting the word out.
 

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When you take the shift lever out of "park" don't you have to apply the brake? I towed a 36ft 5th wheel camper 14000 miles this summer and never had problems with the trailer battery not charging. I think the brake application is only to activate the charging then the system is good and the battery on the trailer is all set.
 

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I used an electric brake magnet that I connected to a 7-way trailer connectors. Them, it will charge you battery. See this video:
 

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I fixed this exact problem last weekend.

Replace fuse 65 (30 amp type M fuse). After check "+" on 7 pin trailer after stepping on the brake once. Should have 13.7-14 volts.
 

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If you have a trailer tow module and are tired of dealing with this nonsense I see no reason why you couldn't re-wire the "charge" wire to an upfitter switch if equipped. Has anyone done that?
 

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Connecting WHAT exactly and for what model year truck? The 12v and reverse lamp circuits could be used for custom purposes as many trailers will not use either circuit and can be repurposed. There are full bulletins on the upfitter switches and the customer access wiring to help you... I can show you the way to the correct bulletin.
 

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I was responding to this post.
I have a 2017 f-450 and I am wanting to us upfitter switch to turn on trailer battery charge and help is appreciated.
 

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OK. So you are aware that the battery charge on 2017's are module controlled. What you are asking is to re-wire the trailer tow charge circuit to an upfitter switch. USING THE ATTACHED BULLETIN run a wire of the appropriate gauge from the left rear of the engine compartment to the trailer tow harness connector. Match the gauge - I am guessing it's 14-16 ga. Protect the wire you run with convoluted covering and secure it away from moving and hot parts under the chassis. If you can find the orange wire in the harness at the left wheel well it would make a much neater installation.

Connect to the #5 or #6 upfitter switch wire and to the orange wire going into the trailer tow connector. Those ae 40 amp circuits. Pay attention to the method used to seal the blunt cut upfitter wires under the hood and employ the same method to seal the orange wire you are cutting to preserve the integrity of the circuit/harness. I recommend you not set the upfitter switch to be powered with the ignition off.

Let us know how it woks out for you!
 

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