Trailer brake disconnected warning....over and over

[DonFitzwater]

Has anyone else out here run into this problem? I've got a 2019 that doesn't seem to like my trailer with electric brakes. My 2015 has the same system and no problems pulling the same trailer. I've been over the trailer twice and cannot find any wiring problems, etc that would cause a circuit failure. I did 1k miles this weekend with the dash dinging nearly the entire trip.

Do any of you fine folks have a decent theory of operation of how this system works?

 

[sag2]

It measures the resistance of the brake circuit. You have a problem, you just have not found it yet. I borrowed a car trailer from a buddy and had the same problem. Finally fixed it by replacing the brake circuit wires. That was after I replaced the brake and backing plate assemblies. It dinged all the way home from his house, and there was no way I was going to put up with that to Colorado and back. By the time he got the trailer back it had new brakes, new wiring, two new tires, and lights. My wife said rent one next time, it will be cheaper!
And don't forget the 7 way plug contacts.

 

[DonFitzwater]

It measures the resistance of the brake circuit. You have a problem, you just have not found it yet. I borrowed a car trailer from a buddy and had the same problem. Finally fixed it by replacing the brake circuit wires. That was after I replaced the brake and backing plate assemblies. It dinged all the way home from his house, and there was no way I was going to put up with that to Colorado and back. By the time he got the trailer back it had new brakes, new wiring, two new tires, and lights. My wife said rent one next time, it will be cheaper!
And don't forget the 7 way plug contacts.

I just don't understand why this trailer doesn't cause the problem on my 2015.....I'm going to gut the trailer this weekend coming up and see what I find.

 

[R.Taylor]

Ground ( battery neg - ) issues can cause these issues too.... I had a trailer that would do the same, I went over and re terminated all the neg ends, Cleaned metal to metal mating surfaces and tightened down various nuts and bolts, Worked perfect afterwards. Your 15' brake controller may not be as "smart" as your 19's as the new trucks have more "computing power" ie capability to monitor more parameters in real-time.

 

[AH64ID]

Check the plug and make sure the connections are clean/tight. I’ve had that issue with a mildly corroded plug.

 

[DonFitzwater]

Check the plug and make sure the connections are clean/tight. I’ve had that issue with a mildly corroded plug.

I stopped in Anchorage and got a new plug and replaced mine.....no joy. Like I said, going to go through the trailer again this weekend and replace one part at a time until I find it. I towed the trailer in to work with the old 12 valve equipped with the prodigy brake controller and it works great.........grrrrrrrrr

 

[lpennock]

Prodigy is robust. Factory is picky to protect poorly engineered components on the truck.

 

[Dan_69GTX]

Yes, I had a similar issue with 2 trailers. Both were the trailer and not the truck. The smarter the controller the less forgiving it is for issues.

1 trailer had ground wire problems
1 trailer had brake feed (blue wire) problems where it rubbed through and would make intermittent contact with the frame or axle tube.

 

[gsbrockman]

Think I read on TDR once that a member added dielectric grease to the truck end and problems went away....might be worth a try, @DonFitzwater

 

[TFucili]

I had a Brakesmart in my '05, and it squawked an error on I-40 somewhere In Oklahoma. I finally found that the brake wire was run from left to right inside the axle, and the wire was not jacketed or in any loom. The rough surface inside the axle had finally chafed through the insulation. I ended up rewiring the trailer from the tongue back the wiring was so poorly done.

 

[Wiredawg]

Yep, I thank trailer builders trailer wiring skills are way low. I have a utility and dump trailer o need to get some caulking putty and squeeze it around the wires where welders burnt a hole through the metal... irregular shaped and eventual ghost problems inthe making.

Cheers, Ron

 

[JR]

I agree with everyone Don. If you have lights and no/weak brakes your brake circuit system is suspect. Don't know if I mentioned it in the following thread but my 98 towed it prior to hooking to the 14. From plug to magnets is fair game. I had the exact same problem. Almost mounted my Maxbrake through my own ordeal but with the help of the TDR greats I got it resolved.

https://www.turbodieselregister.com/threads/brake-controller-problem.258492/

 

[Axel]

I have had similar issues with my trailer. Dieelectric grease helped, but the fix was plug into the truck and secure with electrical tape ( wrapped around plug and lid) it fixed it. In my case the vibration from the roads constantly told me trailer disconnected with a chime driving me nuts....

 

[LandShark]

Also had similar issues. Turned out to be chaffed wires in the axle tubes. Axles were Dexter and less than one year old! Drill holes were never cleaned up where the wires entered and exited the axle tubes.
Picked up some 12g marine tinned double insulated wire from West Marine and reran the wire. No issues now for 3 years and 15,000 miles of towing.

 

[DeansRedRam]

I have an 18 with only 20k miles. Picked up a BRAND NEW enclosed last weekend and kept getting the SAME message on my truck... pretty pissed especially because everything is new. I have a warranty on the trailer but the place I bought it from is 3 hours away..

Dielectric grease did not work on the plug either.. Going to have to go through the trailer this weekend.. dam wire taps..

 

[Tuesdak]

I would start with the ground wire from the trailer frame to the trailer plug. Then verify the ground is "ok" on the truck. We had one new trailer with the battery wired in backwards. Nearly burned both the truck and trailer down. Smoked pretty good. Trailer went back to the factory to be Uh... rewired. The next load the bumper plug worked but the 5er in bed plug didn't. Found out the ground wire was burned clean off. (Constant random brake disconnected message on the 5er plug.) The reason was every intermittent ground through the hitch would set off the brake controller as it was now missing a good ground.

The above advice for intermittent shorts is good.

 

[Dan_69GTX]

Just remember, a resistance check doesn't mean you have a "good" connection. But it could mean you have a "bad" connection.

If you have a wire that is supposed to be the + side and it measures 1 ohm or less to ground - you have a problem because it shouldn't be that low.

If you measure a ground wire and have 1 ohm or less resistance - is that good? Maybe and maybe not. 1 small strand of copper wire could give you that resistance or a full sized 12 gauge wire could. The later will handle the current to ground needed, the 1 strand will not.

That is very simplified, and hopefully makes sense.

 

[Cummins12V98]

When changing to EOH Disks on my Boat Trailer I did not get my ground wire completely tight. Random "trailer not connected" so I started looking and sure enough my bolt into the trailer frame was not completely tight.

 

[CABOVERBOB]

I'm getting the exact same messages as the OP. Brake magnets are all within spec (3.0-3.9 ohm), fuse appears to be ok, all new wiring from frame to individual brakes (10/2 marine cable, terminal strip, crimp connectors and shrink tubing), and continuity from trailer 7-way plug to distribution terminal strip. Still nothing.

Stealership says controller is functioning properly. Is there a way to test the controller myself ? It obviously will not send voltage unless it detects the brake system present.

TIA

 

[DonFitzwater]

Best of luck to you. I’ve replaced every brake component and wire on my trailer and my 2019 still gives random messages after any trip longer than 30 minutes. I’m pretty sure the truck has a problem.