"Check Trailer Wiring" and "Trailer Brakes Connected" and intermittent loss of trailer brakes

[Boudicca908]

1 hour ago, Ronbrink said:

Most U-Haul trailers have a 4-pin cable since they have surge brakes rather than electric brakes. Will that matter in the pull test you are suggesting

And indeed — though I specifically requested confirmation of 7 pin they only have 4 pin and wiring seems to include no brakes. Of course they sell an adapter, but I don’t think this will tell me anything. I’m on hold… 

[Boudicca908]

14 hours ago, jd1923 said:

Doesn't matter. Your mechanic thought this was the correct junction box and all the right colors are there for a trailer wire harness

OTT told me the junction box was located here. Are you saying that this is not correct? Is there a second junction box not visible in this photo? 

(Reminder: I am checking in only periodically from my phone, as I don’t have WiFi in camp.) 

[jd1923]

2 hours ago, Boudicca908 said:

Of course they sell an adapter, but I don’t think this will tell me anything. I’m on hold… 

Correct, 4-pin harness is for small trailers without brakes. 4 pins  only connects turn signals and brakes lights.

They’re wasting your time. You need a heavier trailer, large cargo trailer, car hauler, anything with 7-blade plug like your Oliver!

Edited yesterday at 04:53 PM by jd1923

[jd1923]

1 hour ago, Boudicca908 said:

Are you saying that this is not correct?

No, I’m agreeing it is likely correct because all the right wire colors are there for a trailer wiring harness. Blue wire is power to brakes.

[ScottyGS]

Talking to JD1923 now and I was telling him about a "trailer disconnect" problem I had years back with my Ford F150.  What solved it was the "Tow Ready 20142".  

https://www.reeseprod.com/product/20142_trailer-connector-adapter-7-to-7-way

It "fools" the truck that there is enough electrical feedback to keep that message from happening.    It's not that expensive, less than $30. 

You might try it.  It solved a very vexxing problem for me. 

Good Luck,

Scotty 

 

[jd1923]

9 minutes ago, ScottyGS said:

Talking to JD1923 now and I was telling him about a "trailer disconnect" problem I had years back with my Ford F150.  What solved it was the "Tow Ready 20142".  

https://www.reeseprod.com/product/20142_trailer-connector-adapter-7-to-7-way

It "fools" the truck that there is enough electrical feedback to keep that message from happening.    It's not that expensive, less than $30. 

You might try it.  It solved a very vexxing problem for me. 

Good Luck,

Scotty 

Thanks Scotty, this is very helpful and adds a new twist!

The Oliver has LED lights for brake, reverse and taillights. The low amp draw of LEDs may not register with the factory brake controllers, cause for the error codes.

@Boudicca908's truck is GM vs. Ford but could still be the same issue.
This is worth a try!

If true in this case, there could be nothing wrong with the factory brake controller, nothing wrong with Oliver trailer wiring, just the factory controller not playing well with LED trailer lighting, wow!

Learning this, the U-Haul trailer test I suggested would not be conclusive! If U-Haul trailers have standard automotive incandescent lights the factory controller would not show error with the U-Haul but only trailers like the Oliver with LED lighting.

Yesterday U-Haul failed to rent a trailer with brakes and 7-blade connection. I would try this $30 device asap and scratch the U-Haul idea for now.

At some point, if you're able to tow a second Oliver and the error messages go away, that would be a viable test showing issues with your Oliver trailer wiring. 

[Boudicca908]

Well…. My Oliver and TV played well together for 3 1/2 years before this issue started. But I will keep this in mind. Thanks @ScottyGS for the additional input. 

[jd1923]

35 minutes ago, Boudicca908 said:

Well…. My Oliver and TV played well together for 3 1/2 years before this issue started. But I will keep this in mind. Thanks @ScottyGS for the additional input. 

Yes good thought, but 3 1/2 years OK, not your issue. 

[Snackchaser]

I don’t want to offend anyone, but I have an entirely different view on this issue.  It might be time to pull in the reins on the piece-meal fixes and take a fresh look.

At lot of the advice provided is based on conventional auto electrics and trailer wiring.  But things are much different with today's vehicles.  There is changing technology with Pulse Width Modulation (PWM) switching, and the way it interfaces with modern LED lighting, and the low-to-ground switching of your Chevy that requires solid grounding.

High resistance grounds and shorts can be hard to locate, and they can cause ultra low currents that will be detected by digital systems of new vehicles.  These include grounds and shorts that might only appear under heavy loads, such as from your brakes.  The heavy loads can cause insulation breakdown and arcing that might not be otherwise detected.  The flickering lights you mentioned might be an artifact of your 2023 truck’s older PWM system and a separate issue, or it could be caused from a poor ground.  It could also be caused from a failing brake controller for example.

I agree that it’s most likely a trailer wiring issue, but I wouldn’t go rewiring the 7-pin or axle wiring just yet, or renting a u-haul with a 4-pin adapter because you will not get definitive answers.  Unfortunately, new grommets will not help at this point either, the wires were already taped.  The breakaway switch amperage will be ambiguous too.  A direct short would smoke the wire, a high resistance short would be lost within the range of 9-12 amps for the 4 brake coils.

But there are enough clues to point to a potential ground issue, so a ground check would a good start for most DIY folks.  The trailer is grounded to the TV in 2-ways.  Through the hitch ball, and via the 7-pin ground wire.  The ball ground can be iffy, so the wire ground is important!  You can see the black ground wires in your junction box picture, they are connected to studs that are grounded to the trailer chassis.  A good place to start checking.

Use a multimeter on ohm’s setting.  Find a good ground on the TV for grounding one of the meter leads, and then start checking ground points on the trailer with the other lead while jiggling wires, including those on the axle.  You will need two people, and maybe jumper cables to extend the test lead length.  You should have fairly consistent low ohms readings. You might get lucky and find a loose connection. 

However, it sounds like various technicians have already checked for obvious problems, so at this point  you are really in the territory of an Auto Electric specialist with proper logging instruments to test for intermittent problems and the ability to accurately trace circuit continuity.  Auto electrics is a field of it’s own, and they are far more knowledgable that the dealers and regular mechanics.

Just my two-cents.  Good luck!  Geoff