Trailer Brakes Not Working

RamblinFever · July 8, 2016

Just bought a 2016 2500HD LTZ CC 6 weeks ago. Purchased a 2011 5th wheel shortly after. Everything worked fine from dealer to home. Two days ago moved triailer to check other things. No power to the brakes. Checked today for power, outlet plug had power to everything except the brakes. A good friend in NV bought the same truck and had problems from the beginning with error messages. Had the truck to the dealer and nearly new trailer to its dealer. Both dealers pointing the finger at each other after the truck had been there 6 to 8 times within a month. GM tech rep. said it is a small but common problem with HDs with factory brake controller. Figuring I'll take my truck to the dealer tomorrow. Anyone got some words of wisdom. Sure not taking a 10,000 lb trailer anywhere with controller problem.

sugarjohnson · July 8, 2016

Check the 30 amp micro fuse in fuse box under the hood. When my trailer had issues it blew this fuse. If fuse is blown you won't find one at an auto store it's a new type. Have to get it online or from dealer. If it's blown swap it with the 12v outlet fuse under the hood they are the same type and check for power. If you get power and it blows again I would bet you have a short in trailer brake wiring. It took some searching to find mine. Pinched wire and wires in one drum were worn through on brand new 5th wheel.

Sent from my SM-G920V using Tapatalk

3rd gmc happy · September 9, 2016

Check your trailer wiring That happened to me and the breakaway switch was the problem disconnect the wire to it and see if you get the same message but fix it...

Steve9355 · January 10, 2017

2015 gmc duramax. I have read all the posts and I have the same problems with the messages and the brakes. I also have a power the my trailer reverse lights all the time. I had to tape them off to travel this past weekend. The rest of the lights seem to work but no trailer brakes and reverse always on. Does anyone have this problem. Stopped in for a quick check at the dealer. $75 later and $7 for shop supplies. They told me I needed a new plug on the truck. They said it was corrosion. I took it apart and checked it. Same problems just behind the outer plug. This area is sealed and greased, no corrosion. I pull 4 different trailers with this truck and none of the brakes work. All 4 trailers work perfectly with my 06 Duramax.

paddykean · July 4, 2017

I lost brakes on my RV trailer traveling on Interstate and pulled off at rest stop. Checked plug, cleaned the plug, male and female, sprayed with WD 40. Still no brakes. Crawled under RV and checked for voltage at each wheel. Nothing.All RV lights functioned. Looked for fuse but could not release hood latch. I pulled the breakaway switch. Brakes locked up. Went to to owners manual and on pg 154 found that problem must have been anticipated. There it said turn ignition off, then back on. Fault cleared, got brakes again. Twice more it occurred. Got to stop vehicle, shut it off and restart. took to dealer at home. Nothing showed up on their diagnostic tool.

The next week I bought another RV. Guess what....same happening. New trailer, same result. Nothing showed on diagnostics . Now they want me to drag my RV in. Why no failsafe on brakes. Not hardwired,There's a send and a receive module. Two black boxes. I want to see a blown fuse or smoking wire tattletale, like on my other tow vehicles.

I've hauled all kinds of trailers over the years. Never seen or heard of such a thing, til now.

Anyone have a clue what's happening? I'm a wreck waiting to happen.

HeliMark · July 4, 2017

I lost brakes on my RV trailer traveling on Interstate and pulled off at rest stop. Checked plug, cleaned the plug, male and female, sprayed with WD 40. No brakes. Crawled under RV and check for voltage at each wheel. nothing.All RV lights functioned. Looked for fuse but could not release hood latch. I pulled the breakaway switch. Brakes locked up. Went to to owners manual and on pg 154 found that problem must have been anticipated. There it said turn ignition off, then back on. Fault cleared, got brakes again. Twice more it occurred. Got to stop vehicle, shut it off and restart. took to dealerat home. Nothing showed up on their diagnostic tool.

The next week I bught another RV. Gouess what....same happening. New trailer, same result. Nothing showed on diagnostics . Now they want me to drag my RV in. Why no failsafe on brakes. Not hardwired,There's a send and a receive module. Two black boxes.

Anyone have a clue what's happening? I'm a wreck waiting to happen.

First question is are you getting any warnings on the DIC. Is the truck showing that the trailer is connected when you lose the brakes? With multiple trailers, most likely it is the truck. And if you unplug/plug or turn on/off your truck and it starts working again, most likely it is not a fuse. At that point, I would say you have a bad plug or wiring that needs to be replaced.

I have a '16 and have lost my trailer brakes several times on the freeway pulling. End result after three different dealer visits is they replaced the whole plug due to the last time seeing "weird" voltage. So far so good. But make sure if you get a new one, or clean the existing one, you fill it with dielectric grease. Found water in mine several times. Also, you may not throw any codes that even the dealer could read when this happens, at least mine didn't the 6+ times they went out. Not sure why it doesn't with that type of failure.

Mark

azsheepdog · July 4, 2017

I have found the same issue with my truck. The odd thing is, that if I have the truck running and hook up I get the service trailer brake MSG. If I have the truck shut down and then start up after I am all hooked everything is just fine. If I shut down after a powered hook up it doesn't help. Truck has to be shut down before hook up.

paddykean · July 5, 2017

First question is are you getting any warnings on the DIC. Is the truck showing that the trailer is connected when you lose the brakes? With multiple trailers, most likely it is the truck. And if you unplug/plug or turn on/off your truck and it starts working again, most likely it is not a fuse. At that point, I would say you have a bad plug or wiring that needs to be replaced.

I have a '16 and have lost my trailer brakes several times on the freeway pulling. End result after three different dealer visits is they replaced the whole plug due to the last time seeing "weird" voltage. So far so good. But make sure if you get a new one, or clean the existing one, you fill it with dielectric grease. Found water in mine several times. Also, you may not throw any codes that even the dealer could read when this happens, at least mine didn't the 6+ times they went out. Not sure why it doesn't with that type of failure.

Mark

Thanks Mark,

I replied to you on email. dont know if you saw it. I'm taking the whole rig in Mon, 7/10. I'll let you know the outcome.

Pat Kean

HeliMark · July 5, 2017

Thanks Mark,

I replied to you on email. dont know if you saw it. I'm taking the whole rig in Mon, 7/10. I'll let you know the outcome.

Pat Kean

For some reason, I have not. If you would like to resend, that would be great. Otherwise I will be interested in what happens.

The dealer can plug the computer into the trailer plug and simulate a trailer, which may help. Because everything is so connected on the truck, when mine set off a code, it was for the ABS, wheel sensors, and the tranny!

Every time I hook up, I wonder if it will work the whole trip. Not good. In May I pulled my trailer for little over a week with no problems, but next week I leave for a month trip. I am keeping my fingers crossed. And yes, the possibility of trading in on a different truck has been a consideration if this happens again.

Mark

paddykean · July 5, 2017

For some reason, I have not. If you would like to resend, that would be great. Otherwise I will be interested in what happens.

The dealer can plug the computer into the trailer plug and simulate a trailer, which may help. Because everything is so connected on the truck, when mine set off a code, it was for the ABS, wheel sensors, and the tranny!

Every time I hook up, I wonder if it will work the whole trip. Not good. In May I pulled my trailer for little over a week with no problems, but next week I leave for a month trip. I am keeping my fingers crossed. And yes, the possibility of trading in on a different truck has been a consideration if this happens again.

Mark

paddykean · July 5, 2017

This problem is getting real scary. We too are leaving, for the month of Aug.This truck is my last "hurah". It's financed for the rest of my life. Can't get rid of it. Is the lemon law something to resort to if this continues? Again, truck and trailer going Mon. to dealer.

This whole mess goes back to design fault and should be rectified by GM. This is a class action case if crashes can be pinned to crappy engineering.

Pat

HeliMark · July 6, 2017

Lemon laws are different for each state, so you would need to check to see what it would entail. Of course if you do get to that level, they will fight with you. Take it to the dealer (as you are) and hope that the problem can be found and fixed. And as always, make sure everything is documented. Pain in the ass, but as they say, "it is, what it is".

Make sure your dealer has some concept of what a truck is used for (not a grocery getter). Not that common these days.

And again, make sure after they check the plug, that they fill it, or you, with dielectric grease. Seems to be water is the leading cause.

Mark

Silver16 · July 6, 2017

Spray contact cleaner on the plug and receptacle. Plug in and out a few times. Spray again and hook up. Should be G2G. Lack of continuous use causes the interfaces to corrode some. Spraying cleaner and plugging in and out renews the connection. Good place to start for troubleshooting a trailer connection.

paddykean · July 6, 2017

That's all b.s.. When I step on the brakes I expect them to work, high resistance be dammed, wire open at brake, be dammed. I smoke a wire, I've found the problem. Fuse blown, easy fix. I want to put a real brake control on, with hard wire all the way. I expect their black boxes would disable truck.