Break system is making scratching noises as if it is a caliber breaking problem or a caliber piston problem, it is also setting off the trailer breaking system light on the dash as well as the trail traction control light.

- Cathedral City, CA, USA

Braking vehicle will cause brake pedal to vibrate and become soft while pressing it and requires more effort to stop vehicle. Service brake assist light laminates on info system. I know there is a recall for this currently but my vehicle is not listed for this all though i have the same issues. Recall is N202300860.

- Billings, MT, USA

I purchased my 2018 GMC Sierra 1500 pickup truck new in 2018. To date it only has 28K miles on it. I have never used the trailer breaking system that it came equipped with. On 12/24/22 we were traveling to a family function for Christmas. The "service trailer break system" warning message came on and the chime chimed continuously until I got to my destination, about an hour away. This chime was very distracting and there was no way to turn it off. After arriving at my destination I turned the truck off hoping it was just a fluke. When I started the truck back up the "service trailer break system" warning light and chime continued. It continued for an hour on my way home. Again, this was very distracting and I was unable to focus 100% of my attention on the road and my driving. Thank fully I made it home okay. On 12/27/22 I took the truck to my mechanic to have him take a look. He said he has heard of this issue with these pickups. His diagnostic confirmed that the trailer breaking switch (on the dash) was functioning properly but said that the chassis control module was likely the culprit. He replaced the control module and it had to be programed by a factory technician. After this part was replaced the warning light or chime does not come on anymore. I have the defective part for inspection and the bill totaling $1191.86 for the repair upon request.

- Lake Oswego, OR, USA

I purchased this 2018 GMC pickup in May 2021. Starting in Nov 2022 I started getting a sporadic SERVICE TRAILER BRAKE SYSTEM warning light and chime. I have never towed a trailer using this trailer brake system on the vehicle, but the warnings come on sporadically. I have done some research and found this is not an isolated case as others have reported the same problem. Some owners have replaced the dashboard controller at their own expense, however this is now a well documented problem that goes beyond an isolated case. This is a defect of the trailer brake controller and should be recalled by GM at GM expense. It is a hazard to driving when the visual and audible chime come on sporadically. It's a distraction to safe driving and requires immediate intervention. I did advise my local dealer of the problem when the vehicle was serviced Dec 2022, however they did not have a technician available to work the problem. So I continue receiving the visual and audible warning every time I drive the vehicle. Please highlight this problem within your organization for a possible safety recall.

- Waupaca, WI, USA

Breaks are not working

- Magnolia, TX, USA

While driving 35 miles per hour in the early morning hours I came to a 4-way intersection and applied the brakes slowly. Suddenly, I lost all power in the brakes and the steering wheel locked up. The lights, and stereo remained on, and my dash board display immediately showed a red check engine light. I immediately turn on my hazard lights, turned the ignition key off and tried to restart the truck. There was no clicking sounds. The truck would not start but the lights dimmed and the dash display now showed an intermittent yellow, flickering check engine light. After roughly 30 minutes while waiting for AAA to arrive I tried the ignition key and the truck started up with a red check engine light. Rather than attempting to drive I had AAA tow my vehicle to the Chevrolet dealership where I purchased the truck.

- Eugene, OR, USA

Received an error on the dash saying "Service Brake Assist". At the same time the brake pedal became very stiff and braking power was decreased significantly. I have received this same message and brake pedal stiffness with reduced braking power three times in the last 4 days.

- Lompoc, CA, USA

The service alert for the trailer brakes keeps going off constantly and continues to go off persistently almost making the vehicle undriveable. I was informed to file a complaint with your company by my local dealership as this is a recurring issue with GMC trucks.

- Birmingham, AL, USA

I am getting a service alert for the Trailer Brake System. It is constant and loud and distracting and a significant safety hazard, not only because of the distraction, but also because it renders trailer brakes completely useless

- Youngsville, LA, USA

message and alarm kept going off on our truck "Service Trailer Brake". We are not towing a trailer, nor had we had a trailer hooked to this vehicle since 2019. It began only going off occasionally, but within a few weeks it was going off constantly. It would show repeatedly on the dash and the alarm would sound over and over. Trying to turn off the system was not successful, no matter how many times we hit dismiss. It was totally distracting and worrisome that something was wrong with our braking system in general. constant alarm and dash display made driving a very distracted experience. It is so loud that you cannot hear other outside noises. We were also concerned about the safety of our regular braking system. called the dealer where our truck is regularly serviced. They immediately said "Is it the Trailer Assist Alarm?," so it was obvious that this is happening to other owners regularly. It took several days to get in for an appointment. The shop mgr helped us to locate and pull the alarm fuse to stop the noise, so we could drive it to the dealership later in the week. The display was still going off when I pulled the truck into the dealership, as it has done all the way there (17miles from my home). was inspected by the GM dealership (Schwarz, INC. Honesdale, PA) and the defective switch was replaced at a cost to us of $127.14 on 08/11/2022. *This issue started several months ago (Feb 2022?), but it was a one time thing. So, we thought it was just a fluke. Then, a month or so ago it started again, but was happening only once or twice and would then disappear for days. Then, 2 weeks ago it began to happen continuously.

- Lake Ariel, PA, USA

I was stopped at a fast food drive thru and then I tried to go to the next window and the truck wouldn-€™t move at all it will just rev so I put it in parked turned off the truck and turn it back on put it on drive and was able to move for like 40 ft then it did it again so I had it towed to my home

- Seagoville , TX, USA

Trailer brake modulator on 2018 GMC Sierra does not consistently signal trail brakes to work when needed on our 7,500 pound RV trailer. GMC dealer eventually found that the battery cables were undersized as installed with the factory towing package on the 2018 GMC Sierra. The undersized battery cables do not consistently deliver adequate voltage to the trailer brake modulator on the GMC Sierra, so inconsistent electric brake function for our 7,500 pound RV trailer. Dealer had difficulty diagnosing the problem as being the wrong factory-installed battery cables to go with the factory-installed trailer towing package. So it cost us $1,600 to have the GMC dealer correct a problem caused by the GMC factory installing undersized battery cables. Fortunately, this did not result in a collision for us, but it might for someone else. Our 2018 GMC Sierra kept sending vague, randomly timed warnings to the dashboard to "Check Trailer Wiring." Very frightening, dangerous and costly (for us) mistake by GMC. Will the brakes work this time, or fail on the way home? Problem started in 2021 RV season, but took awhile for us to recognize the need to take to the GMC dealer for them to diagnose base cause. Took time for us to experiment changing trailer wiring connector on bumper and trailer brake control on the dash. Work for awhile, then fail. Work for awhile, then fail. Arrrrgh! Ask GMC to put more adequate battery cables on ALL their vehicles, please.

- Merrifield, MN, USA

SERVICE TRAILER BRAKE SYSTEM - warning

- Kansas City, MO, USA

-€œService- trailer brake system-€ light keeps coming on. It is super repetitive. It comes on about every 30 seconds. It-€™s a loud beep that lasts quite a few seconds. Eventually, the beeping did not stop until the truck was stopped. Truck was just bought yesterday. Happens at any speed, even when stopped.

- Old Hickory, TN, USA

Yesterday afternoon I heard a beeping noise that was persistent and it said trailer brake check the same alert showed up today making it impossible to drive safely with the alert popping up every min

- Houston, TX, USA

While driving parking lot speeds, when I pressed the brake pedal, it was very very difficult to push causing me to nearly rear end the car in front of me. This happened intermittently during a short time frame (5 minutes). While standing on the brake pedal hoping to stop in time, the brake pedal shook like the Antilock brakes were activating. This caused it to be even more difficult to stop in time. My vehicle is currently at my local dealership's service shop. When the issue occurred, a message stating "Service Brake Assist" popped up in my display.

- Chubbuck, ID, USA

Im getting a service trailer brake system soon message on dash.

- Brooksville, FL, USA

At 50,000 miles the "service trailer brake system" error message appears constantly due to factory defects and its very common. These trucks should be recalled everyone is in danger on the roads and its a very common problem. I have not taken it to the dealer because i should not have to pay for this very common problem, it should be recalled.

- Carolina Beach, NC, USA

The truck displayed warning lights for ABS, traction control, trailer brakes, and front park assist. Additionally speed control (cruise) did not function. This presented a safety issue. I took to dealer asap. They repaired by replacing left rear wheel speed sensor. Cost about $216. Appears to work correctly at this time.

- Mt. Vernon, IL, USA

The first thing that happened was that all of the electrical systems on my truck went out and my truck would not start. It finally started but it would not move finally it would move but very slowly this happened on 11/20/2019 I have documentation through onstar for this incident. My brakes started slipping on 07/01/2020 and still do not work properly. My transmission has never shifted correctly. When I accelerate or when I slow down there is a shudder and a jerking sound. After sitting for a while when my truck is put in reverse it hesitates and then seems to jump into gear.

- Owens Cross Roads, AL, USA