Non-functional powered tongue jack when connected to my 2019 F-150

[Herseraph18]

So we bought a used travel trailer last year, everything with it has been great overall, but it came with a powered tongue jack that the previous owners installed as they were quite old. It's also an old trailer, but that's beside the point. Anyway, it worked fine with their Chevy, but it's never worked with my F-150. I've tried everything, short of switching out the one 15A fuse that *might* be causing an issue, but I came here specifically to ask if that could be the cause of it first anyway. I know, I know, I could and should just change the fuse, and I will, but I still wanted to ask here first if that could even be the cause. I really don't mind manually cranking it, but as we get older as well, it would be nice to have the electric jack.

If there's any relevant info that you may need to help with my problem, feel free to ask and I'll try to add as much as I can.

Sponsored

 

[Ricksc]

My trailer jack is powered from the trailer batteries. I can use it with out truck being hooked up.

 

[Herseraph18]

My trailer jack is powered from the trailer batteries. I can use it with out truck being hooked up.

Sadly mine is not, it's meant to hook up to my 7 pin connection on my truck, which I do, but no power goes to it. I've been told by others, I don't know if this true or not, but if it doesn't work right away, you're supposed to get in to the truck and press and hold the brake pedal for a few seconds and it'll recognize it, but even that doesn't work. Supposedly that has something to do with the 7 pin from the electric tongue jack not being the same as the one from the travel trailer as it doesn't have the same amount of wires in it so the truck doesn't fully recognize it as a 7 pin connection so it doesn't accept it when you connect it, so that's why you're supposed to step on the brake pedal to activate it. So the theory kinda makes sense, but it didn't fix my issue anyway. Unless I did something wrong when I tried it multiple times over the past year.

 

[Herseraph18]

My trailer jack is powered from the trailer batteries. I can use it with out truck being hooked up.

Though I'm curious, how is yours wired up? Is it wired directly into your battery, and did it come pre-installed on your trailer, or was it added after? Mine was an aftermarket add-on.

 

[Ricksc]

It was on mine when I bought it. I bought it used from the dealer that installed it new. It’s tied to trailer batteries haven’t looked at it. From how you describe yours sounds like they were taken power from brake lights. Pretty strange. Most I have seen are wired to trailer battery. Have you googled your powered jack and see how they say to wire it. Seems like 7 pin connectors should be a common setup.

 

[JEB]

So we bought a used travel trailer last year, everything with it has been great overall, but it came with a powered tongue jack that the previous owners installed as they were quite old. It's also an old trailer, but that's beside the point. Anyway, it worked fine with their Chevy, but it's never worked with my F-150. I've tried everything, short of switching out the one 15A fuse that *might* be causing an issue, but I came here specifically to ask if that could be the cause of it first anyway. I know, I know, I could and should just change the fuse, and I will, but I still wanted to ask here first if that could even be the cause. I really don't mind manually cranking it, but as we get older as well, it would be nice to have the electric jack.

If there's any relevant info that you may need to help with my problem, feel free to ask and I'll try to add as much as I can.

You might be out of luck trying to tap 12v power directly from the 7-way. The set up worked for the previous owner because Chevys are wired differently from Fords. Chevys provide constant 12v power via the 7-way. Fords do not. Fords have a so-called “smart” 7-way which will only energize the 12v pin if it senses the presence of a trailer. I’m not entirely sure how much of the 7-way has to be engaged before the truck detects a trailer and energizes 12v pin, but I think it requires at minimum resistance on the brake light pin.

 

[Herseraph18]

You might be out of luck trying to tap 12v power directly from the 7-way. The set up worked for the previous owner because Chevys are wired differently from Fords. Chevys provide constant 12v power via the 7-way. Fords do not. Fords have a so-called “smart” 7-way which will only energize the 12v pin if it senses the presence of a trailer. I’m not entirely sure how much of the 7-way has to be engaged before the truck detects a trailer and energizes 12v pin, but I think it requires at minimum resistance on the brake light pin.

That's my understanding as well, which is why a few people have recommended doing the get in and push on the brake pedal trick, it's supposedly meant to energize the 12v pin so it'll detect it as a trailer somehow so it will work properly. But I don't know if maybe I'm doing it wrong, or if that's just not a real thing that actually works or not.

Hmm, though I just had a thought, could I potentially stick a fuse in to the 7 pin harness on my tongue jack and have that power it? Like some people do when they stick fuses into their 7 pin harness on their trailer to power lights on the outside of the trailer when they are parked? You know what I'm talking about?

 

[Herseraph18]

It was on mine when I bought it. I bought it used from the dealer that installed it new. It’s tied to trailer batteries haven’t looked at it. From how you describe yours sounds like they were taken power from brake lights. Pretty strange. Most I have seen are wired to trailer battery. Have you googled your powered jack and see how they say to wire it. Seems like 7 pin connectors should be a common setup.

Funny, most I've seen have been the opposite, wired like mine, and plugged in to the 7 pin, lol. I suppose if I get desperate, I could cut the wires on the tongue jack wire harness and potentially just jury rig a connection to my batteries ?

 

[JEB]

That's my understanding as well, which is why a few people have recommended doing the get in and push on the brake pedal trick, it's supposedly meant to energize the 12v pin so it'll detect it as a trailer somehow so it will work properly. But I don't know if maybe I'm doing it wrong, or if that's just not a real thing that actually works or not.

Hmm, though I just had a thought, could I potentially stick a fuse in to the 7 pin harness on my tongue jack and have that power it? Like some people do when they stick fuses into their 7 pin harness on their trailer to power lights on the outside of the trailer when they are parked? You know what I'm talking about?

I get the gist of what you’re saying but I don’t think it’s going to be that easy to trick the 7-way into thinking a trailer is plugged in. I have a 7-way diagnostic adapter that looks like this: https://www.amazon.com/MaxxHaul-50155-Trailer-Wiring-Tester/dp/B07QX2L7K5/ref=sr_1_16?crid=29TCDWKMFRC3W&dib=eyJ2IjoiMSJ9.CM7iMMLz2HDrb21NBVCSEXYge8FHT1K9_VH7YvtjLoXnQs8bVJtJRupcUODzXJxkPjhHlmSnFYB9MIEqeboyq-TvUwd_NXBMYgaZ0wscFaCbC-uldquvFxNfn4No9bXqhn2uGIgGxJnQmoMV6KqoUyPnHWJBxukvke6tVBKDK59XkwqFVKJvYLk_dfukdHB-bqemqU426ZoLbd2-kZOsUoodYGZN9UnJMWmw18PPXdsGwMjK-FB-7nlcwx10R_x-xLZ_jC4DnsW-BjoEwCWX210IfTXPQxDZC2i0AugnxJ8.RfqxsEZ4gyjY014LGa23-XnfOUtu9BgeoZSPuwCizI8&dib_tag=se&keywords=7-way+tester&qid=1748120055&sprefix=7-way,aps,150&sr=8-16&th=1. I cannot get the 12v diagnostic light to light up no matter what I do. But when I plug in a bona-fide trailer, with brakes, lights, batteries, etc., the 12v pin works just fine and provides positive voltage to the house batteries. The same adapter on my Chevy showed 12v on the 12v pin any time I plugged it in.

 

[Ricksc]

Need to make sure your center pin has 12 volts. Have read other post where the center pin had no power due to missing fuse.
Looks like that’s the pin the use for wiring Jack.

 

[Ricksc]

https://www.f150forum.com/f118/fuse-12-volt-pin-7-pin-plug-494552/

Found this on another forum, you have got my curiosity going. Read lots of people with this issue in the past. Kind of sounds like what you’re trying. But says new computerized trucks don’t power the 12 volt pin unless trailer battery calls for it.

 

[Buyer2021]

Have read other post where the center pin had no power due to missing fuse.
Looks like that’s the pin the use for wiring Jack.

NO, the center pin is not for battery charging / aux 12V power:

Note the socket key position - on many late model F150's it's on the bottom, everything simply rotated 180 degrees from what is shown above.

This socket pin arrangement has been uniform for all OE F150/250/350 7-pin sockets for decades.

If you doubt, compare to the diagram molded into the socket cover on your F150.

 

[Ricksc]

Multiple use pin. My co worker had this is on a 2020 no power on pin

 

[Ricksc]

Here’s more on that

 

[Ricksc]

Check fuse # 36 in engine bay

Sponsored