Have a 2016 GMC 3500, 6.0 gas job with 57K miles. Constantly now my computer screen beeps "Service Trailer Brake System", even when no trailer is hooked to truck..took to my local trailer guy, he checked my plug port where trailer lights plug in, and we checked all fuses. he said neither is the problem. he says its either the factory built trailer brake controller that was built in dash, or the "Module" that is up under the spare tire. Anyone ever have this issue?He said it would be a guessing game for him. I hate to take it to the stealership for diagnosis though....

Not that anyone cares lol, but I figured I would update this post incase someone searches this in the future. I ended up trying out the cheapest and easiest part to replace, bascially throwing parts at it, and bam it worked. My factory trailer brake controller was the problem. I had one sent via Amazon, $43 later changed it out and works like new. No more stupid computer telling me to service trailer brake system. I love my GMC's, but kinda crazy the factory brake controller went bad on a 3 year old truck with 57k miles. O well, could be worse

thanks for the update, i care about them.

I would take apart the connectors behind the bumper and make sure none have moisture in them. Assuming there isn't a failure with the brake controller, it's seeing a connection to the brake actuating wire at the trailer connector. That could be moisture, rodent damage, etc.

Are you not under warranty? If you are I'd take it to the dealer and let them sort out the issue.

My 08 was doing that this Winter first time I had seen it before. Moisture or issue at the rear plug is cause.

"Service trailer brake system" on 2016 GMC | Good Sam Community

jabres
Explorer II
Jan 26, 2019
Not that anyone cares lol, but I figured I would update this post incase someone searches this in the future.
I ended up trying out the cheapest and easiest part to replace, bascially throwing parts at it, and bam it worked. My factory trailer brake controller was the problem. I had one sent via Amazon, $43 later changed it out and works like new. No more stupid computer telling me to service trailer brake system. I love my GMC's, but kinda crazy the factory brake controller went bad on a 3 year old truck with 57k miles. O well, could be worse
- misterroadman
  Explorer
  Oct 14, 2024
  My 2016 2500 constantly shows codes on the screen for the fact same thing , enem the stabil link and ABS & brake light just started
  thank you posting this 👍👍
Dave_H_M
Explorer II
Jan 27, 2019
thanks for the update, i care about them.
ScottG
Nomad
Jan 15, 2019
I would take apart the connectors behind the bumper and make sure none have moisture in them. Assuming there isn't a failure with the brake controller, it's seeing a connection to the brake actuating wire at the trailer connector. That could be moisture, rodent damage, etc.
LIKE2BUILD
Explorer
Jan 15, 2019
Are you not under warranty? If you are I'd take it to the dealer and let them sort out the issue.
ksss
Explorer
Jan 15, 2019
My 08 was doing that this Winter first time I had seen it before. Moisture or issue at the rear plug is cause.
neil57
Explorer
Jan 15, 2019
Friends truck had same issue, was the ground on the module up by spare tire. It’s not expensive to just replace it.
jabres
Explorer II
Jan 15, 2019
Like2build- wish it was, just this year GMC was 3 years 36000 miles, which is kinda a joke.
Fisherman
Explorer
Jan 15, 2019
Maybe a bit of road salt corrosion happening causing electrical gremlins to surface.
Beaker
Explorer
Jan 16, 2019
Had that problem on my 08. Controller replaced under warranty.
deltabravo
Nomad
Jan 16, 2019
Pressure transducer failed on my 2009 back in about 2011.

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"Service trailer brake system" on 2016 GMC

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