Brake Controller

[Joel.j]

Hello!

We have a 2021 294rl and a 2022 GMC Denali HD, with about 18,000 miles of travel with both trailer and truck in question.

We tried to move from our park where we’d been for 2 months yesterday and returned as our trailer brake control would disengage intermittently. We’d get a ding ding ding and the message check trailer connection. When it would go out, the orange light on the brake control would extinguish. Then it would randomly come back and then disconnect again.

We have plugged the truck into other trailers in the park and all seems to work well on those.

We have checked voltage on the connection in at the hitch on the trailer and all seems normal.

This issue makes it difficult to contemplate towing to a repair facility, does anyone have any recommendations on where we might see about checking next? Anyone have this happen?

Thanks!

[jsb5717]

Do you have the adapter for the GM product to supply the full 12v to the trailer connection?

I had that same disconnecting error happening with our RAM last season. I happened to have a Tekonsha controller as a backup so I plugged that in. I still kept getting a disconnect. So I knew that it was either the truck wiring or trailer wiring, not the controller itself. When I did a thorough inspection of our trailer brakes I discovered two issues.

1. I had a broken brake wire inside one of the wheel hubs. Repaired it.
2. I cut and pulled the brake wires from inside the axles. I discovered they had worn, allowing intermittent shorting...hence my intermittent disconnect notification. I rewired the brakes at both axles to the exterior of the axle, using zip ties to secure the wires to the axle to eliminate further rubbing and wear. Brakes have worked perfectly since.

[Daryles]

I had intermittent connections. I used #200 sand paper and contact cleaner to clean the 7 way cable contacts. To get inside the female pins I rolled up a piece.
Then I took the cover off the junction box and gave each wire nut a squeeze with pliers.
That worked for us.
Last year before getting on the road I jacked up the rig and tested the brakes from the pedal and from the break away switch. I had one tire that would not lock up. I discovered the wire inside the drum had worn in two. Easy splice fix.

[twindman]

I had intermittent messages also years back. I would hit the road and anywhere from 1 mile to 30 miles it would go on and soon off. Read on here I think about cleaning the plug connection. So I make it a habit to plug in and unplug 2-3 times before taking off. Also use some stuff (spray?) on the truck connection every few years. I have not had it happen again.

[BBaloo]

I believe in simplism, before taking wheels and hubs apart to get to the brakes, I would put some Dialectric grease on the 7 pin connection. It could be something that simple. I also would agree that it is possible for the wires to wear/loose contact. It is even possible that a squirrel/mouse could have done some damage while you sat at the park.

[77cruiser]

Dielectric grease is a insulator, so that's not a good idea.

[laverdur]

This sounds a lot like what I experienced when the brake wires inside the axles became chaffed and the metal conductor was shorting out against the metal axle tube. It took me a long time to figure this out due to its intermittent nature and inability to duplicate when stopped. Solution: disconnect the brakes from the wires that go through the axle tubes and zip tie new wires to the outside of the axle tubes. Be sure to use a proper wire gauge that will carry the current the brakes need. You can make a cleaner installation by getting a couple strips of plastic wire mold at a home improvement center and zip tying those to the axles to act as cable messenger.

[Randy E]

We had the same problem for over 1000 miles. Ding Ding Ding. Trailer wires disconnected. But everything worked everytime I checked. It turned out to be a wire inside out brake drum. We replaced the drums. The next year the exact same thing happened again. I ended up putting wire ties on the internal brake arm to hold the wires out of the way. It worked.
Then I replaced everything with IS and hydraulic disc brakes.
The attached photo is my wire as found originally.

[sberlin]

Similar problem on our 2018 3701lk w 2015 GMC 3500hd. First the brake wiring was melted so got that fixed but problem persisted. It became finger pointing between GMC & trailer repair shop. Finally ended up at an electronic specialist shop who spent 3 days trying to track it down on the truck. The trailer brakes go first thru a trailer brake module and then a chassis module. They finally replaced the trailer brake module and that fixed the problem.

[Daryles]

The brakes are supposed to have clips on the actuating arm that hold the wires back out of the way.
I had one that was missing the clips and the wires rubbed against the drum and wore through.

I read somewhere about a recall regarding this.

[astrungis]

I had the same problem. It has to do with the GM brake controller receiving feedback from the trailer batteries that are charged by the solar-charged
batteries. The voltage from the batteries are too high and causes the GM brake controller to time out. Please read the substack letter below to help explain. GM is aware of it. I put a "on/off" switch between the solar panel and solar charge controller in addition to a "one-way" diode from the battery line back to the truck. It solved the problem. Good luck! https://rvelectricity.substack.com/p...mly-disconnect