7-way plug not powering turn signals/brake lights

[Bennett52]

My 2022 Adventure will not run my turn signals or brake lights on my trailer. The running lights are fine. Took it to a Winnebago Dealer and he could not figure it out. Said it was a Ford problem so took it there. They said it is Winnebago problem. $300 later I still do not have power at the plug on the hitch. The lights work fine on the coach, any suggestions. I did find a blown fuse in the panel under the hood. Changed it but still have no blinkers or stop lights . The trailer works fine on my car so everything on the trailer is good.

[be happy]

I do not know if this will help as different year and model, but. My 07 Meridian has in the electric bay a covered panel that has all kinds of fuses for the 7pin connection. I would look around as there must be some sort of fuse panel.

Hopefully someone with your model will come on for more direct info.

[Scotty B]

So, happened to me after my first campground. I plugged the cord into the Bronco upside down and it blew a fuse in the engine bay of the Coach. 15 amp and might have been slot 15, but almost a couple years now so not sure. Seems someone would have diagnosed that, but thought I would pass it on...

[Morich]

Logic seems to be in short supply in your end of the world!

If three separate circuits, left turn, right turn, and stop lights, are all not working, I can't imagine it being a power problem if the lights on the RV work!!
I CAN easily see it being the ground at the plug being a problem, since they all use the same ground pin!
Even a $3 mechanic should be able to figure this one!

It's a pretty short distance from the taillights down to the trailer plug!

[wahoonc]

Ford used to run the trailer stuff through a separate set of fuses, they were in the main block under the hood on the E and F series. The ground would be easy to check, just run a jumper wire from a clean ground on the frame to the wire terminal on the back of the plug.

Aaron

[Ray,IN]

Turn signals and brake lights on a trailer use the same circuit, never seen a cargo trailer with separate brake and turn signal circuits.
So, this means the first thing I'd do is test those pins for signals/power on the MH. If it were a poor/missing ground problem the tail lights and running lights would not work either, as the ground is one common wire from the MH plug to either the chassis or the battery.
Do not go by pictures when attaching wires to a plug! Go by the markings on the plug terminals. I've seen so many incorrect pictures and diagrams on the internet it's no wonder why folks have troubles with wiring.
If you buy Bargman brand plugs they have the wiring diagram on the plastic packaging and on the plug terminals.

[Morich]

It's always a question if we are getting the full and correct test results from postings but we have to go with what they report, even if it is not always complete.

We don't get which RV it is, so we have to go with what is normal until we know better?

On thing that is reported is that the lights all work right on the RV, so that rules out any fuse or breaker problems on the RV. If the power and ground get to the taillight fixtures and the trailer lights work fine when connected to a different tow vehicle, I see very little room to wonder where the problem is. But that also means we are guessing about who wired the trailer and car!

What they are saying may/may not be correct but if true, it all works until after it gets to the lights on the back of the RV or after it gets past the trailer connector.
That only leaves the 4-6 feet of wire getting from the lights and getting into the plug!
If the OP is telling it straight, there is very little wire exposed along that path and the best place to find damage or opens is at the rear of the connector or the few inches that are exposed right behind it.

That's a good place to wonder why it cost $300 to look for this trouble?

But we don't get lots of details that would tell us what's up, either!
Obvious things like what kind of voltage shows up on the pins of the connectors and what is the ground like on the ground pin?
What kind of trailer is it and who wired it? Is it "normal" wiring or do some of the lights get ground through the trailer hitch and others isolated from frame ground and have to get ground from the RV?
Did it work at one time and stop or is it a case of the trailer wiring never being correct for the RV plug? Is it a trailer built by somebody who knows the drill or is it some homemade that is a one of a kind build?
Maybe the trailer was DIY as well as the car and both are not what the RV has?
That could make it really hard to figure out what was wrong with the RV if it is the car and trailer that are WRONG!

But even if we assumed the worst and the ground wire was cut inside the back wall of the RV, even the worst shade tree mech should figure how to get ground to the trailer!

[l1v3fr33ord1]

My experience is with the V-10-powered F-53 chassis, model years 2001 through 2019. I have no experience with the V-8-powered F-53 chassis, model years 2020 to current. So, everything I say below is based on guesses. The only thing that makes me believe those guesses could be correct and helpful is that Ford has a history of not changing their designs much from model year to model year.

Here are some facts about the F-53 chassis from 2001 through 2020:

1) The turn signal switch provides two sets of outputs. One set is turn signals only. The second set is turn-plus-stop signals.
2) Each of the output sets has its own pair of left-right relays, fed by a common fuse.
3) These fuses are found in the Passenger Compartment Fuse Panel.

After 2006 or so, many, if not most, motorhome manufacturers would wire the turn-only signals to the coach turn lamps, and wire the turn-stop signals to the trailer plug. The coach turn lamp wiring and the trailer turn-stop wiring were not connected together at the rear of the coach.

Looking at the 2022 F-53 owner's manual, fuse section (link here), we see that there are no longer specified fuses or relays for the turn-only signals. I speculate that Ford has moved to a CANbus system to feed the "chassis" lights and signals. But, in the Engine Compartment Fuse Box are these listed fuses:

78 Trailer tow stop lamps
105 Trailer tow right-hand and left-hand stop and direction indicator relay power

Hmm... that sounds similar to pre-2020 F-53 fusing and relay design.

As far as troubleshooting goes, then, I would first apply a 12V test light or voltmeter to look for 12V at the correct pins on the coach hitch connector (3 o'clock and 9 o'clock pins, as in post #4 and also here, with ground at 7 o'clock). Use the hazard switch to put 12V on both the left and right turn-stop signals at once, with the engine off. If you find no 12V on those pins, then check fuses 78 and 105 in the Engine Compartment Fuse Box.

[Morich]

Reason for me to not think it a fuse or supply issue is that they rerport the lights on the back of the RV all work as they should. To me that means the fuses, etc. on the RV are okay.
The RV I have looked at has a second set of wiring connected into the main, somewhere near the lower left side of the frame.
If the wiring to the RV is good and not getting from that wiring down to the trailer connector, I look for the problem at either the connection of one wire group to the main or right at the connector.
But if we make the jump to assume the connector is the standard issue Winnebago normally uses, there are separate circuits for left, right and tail lights. There is also a ground lead as the diagram shows.
That makes it pretty simple to check for the connector being right and find where things are missing.

But the wild card is that lots of people do weird things with trailer wiring and we have no idea what the OP has in their RV, trailer or car!
Maybe the car and trailer are wired in some weird way that makes them work together but the RV is wired to standard which is different!

So it's a guessing game with no answers until we hear more which may never happen!

[Ray,IN]

I just remembered another possible cause; Modern vehicles have separate brake/tail and turn signal light holders. That requires a small device placed in the wiring to combine those signals, it is normally found between the vehicle's trailer plug and the stock vehicle wiring harness. Perhaps there is a faulty connection there.
reference: https://www.electroschematics.com/tr...nal-converter/
https://www.etrailer.com/question-30775.html

[Scotty B]

OK, last try....all the lights on my rig worked fine. It was just the break and turn signals on the Bronco that had issues. Was why we felt safe enough to drive to the next campground before I called my RV guy who installed the Blue Ox for help. And yes, we and the OP have the same year Adventurer. Don't think we've heard from the OP again and we're all trying so hard to help them...frustrating.
You guys are all the best...
Safe travels!

[Scotty B]

I lied, one more post. From the Ford owners manual...only missed the location by one digit. Pretty good for an old fart!
Here in Camp Margarittaville near Orlando. Place is a trip! Anyone ever been?
Will post a new thread on a pixelated bedroom TV that hopefully one of you guys can help with. Unhappy wife is not good. Thanks!

[Morich]

So the first answer should have been?
Check the owners manual!!!

Click to get a better view! Also don't miss the small point on resetting things if you change the battery as that may be new, too!



Sounds like we are only getting parts of the story and not likely to ever know what we are missing! It does show me that my past work with the trailer connections is not longer true!
But if the manual says to check these fuses, that would seem to be a place to start if there is no power to the connector at back.

That leaves me to wonder what they got for the $300 they paid??
Some very basic info missing!

[Farco]

Trailer light circuit has its own fuses

[grtharris]

Bennett52, here's the trailer brake/turn drawing for the 2022 F53 chassis. Note there is only one fuse for both, F105 in the Battery Junction Box.