2018 GMC Sierra 2500

GM Duramax L5P diesel engine electrical connector for #4 fuel injector. This failure caused the Diesel exhaust brake, which controls downhill speed, to disengage, extreme shaking of the vehicle, emissions system warning and speed limiting. This occurred while descending a steep grade while towing a 34 feet long, 10,000 pound trailer. This is a known issue with this diesel engine and documented in GM Technical Service Bulletin 23-NA-027. Inspection and repair at a GM dealership confirmed a known issue with the #4 injector pigtail connector caused by improper wire routing and interference wit the Sound Shield and Valve Cover Heat Shield This was a sudden failure of the #4 pigtail connector with no advance warning. In addition to violent shaking of the vehicle, multiple warnings on the DIC indicating that the Diesel Brake was disengaged, the emission system had an issue, and speed would be limited.

Service Trailer Brake System Warning From time to time, this warning goes off in the vehicle and when it does, it does it constantly. When the warning is dismissed, it does it again seconds later. If it is not dismissed, it does it again seconds later. It is a persistent three ding double chiming that is not only constant, the vehicle is doing it without a trailer connected to it. The GM dealerships we have been to regarding this issue do not know how to fix it since the warning is as intermittent as it is persistent. Once one of the dealerships was finally able to observe the warning themselves, we were told because it does not cause the check engine light to come on, they are not given a code, therefore, they do not know how to address the issue. The Service Engine Brake System warning is not only a persistent auditory nuisance. The warning chime overrides any other audio capability of the vehicle and it will be the only thing the control panel shows. If the warning is dismissed, it comes right back. This means we cannot hear anything else in the vehicle, such as turn signals, and we cannot see anything else on the control panel, such as speed. We can only surmise this issue is some sort of an electrical system malfunction since we do not have a trailer connected to the vehicle when the Service Trailer Brake System warning is coming on. The vehicle has been presenting this persistent warning since we purchased it from a dealership in August of 2022 and the vehicle continues to present this persistent warning intermittently, which will last days to weeks at a time and is not corrected by the engine being turned off and restarted, no matter if the engine is shut off for minutes or days. How much time passes between the persistent Service Engine Brake System warning events can be less than one day to several months later.

While braking ( after being on the highway) all dash gauges turn black, radio shuts off, AC shuts off. Service Stabilitrak light comes on when dash flashes back on. While driving AC turns off, Radio turns off same stabilitrak warning flashes, speedometer turns off. Power steer control went out while trying to turn. Truck put itself in 4 wheel drive when I turned on the trailer assist. Parking assist periodically turns itself off.

I have a 2018 GMC Sierra Duramax Quad-Cab and when it is connected to either my boat, stock trailer, or cargo trailer the lights and electric trailer brakes on the trailers do not work. and the chime from the "Service Trailer Brake" indicator sounds and doesn't stop until I unplug my trailer harness from my truck making it a distraction and an unsafe situation when trying to navigate through traffic(changing lanes, stopping, and other functions needed when hauling trailers). The dealership said it was a module and specified which one and so I elected to replace it myself and it wasn't the issue. I choose to do the work myself as they quoted me a price of $700.00+ to repair the problem.

MY 2018 GMC SIERRA HD EXPERIENCED AN ELECTRICAL SHORT OR OVERLOAD, CAUSING A THERMAL EVENT THAT MELTED AREAS AROUND THE REAR DEFROST CIRCUIT. LOTS OF SMOKE AND BURNING SMELL, BUT LUCKILY, I DID NOT SEE FLAMES. THE EXACT ISSUE IS CURRENTLY BEING ADDRESSED UNDER GM RECALL# "N192265660 REAR WINDOW DEFROSTER THERMAL EVENTS", HOWEVER MY VIN IS NOT INCLUDED. THE ISSUE I HAD IS EXACTLY WHAT IS DESCRIBED AND I BELIEVE SHOULD BE INCLUDED IN THE RECALL. I'VE ATTACHED A FEW IMAGES OF THE BURNED, MELTED AND BROKEN PARTS. AGAIN, I'M LUCKY THERE WAS ONLY SMOKE WHEN THIS HAPPENED, AND NO FIRE. PLEASE REVIEW AND ADVISE

WHILE THE TRUCK WAS UNATTENDED, SMOKE WAS OBSERVED BY A PASSER-BY WHO CALLED THE LOCAL FIRE DEPARTMENT. FIRE DEPT BROKE A WINDOW FOR ACCESS, EXTINGUISHED FIRE. HAULED VEHICLE AWAY FOR SAFEKEEPING. HAPPENED WHILE WE WERE AT A CONDO COMPLEX, VEHICLE PARKED FOR THE EVENING. HEAT INTENSITY AND MELTED PLASTIC INDICATED THAT FIRE OCCURRED IN CONSOLE AREA. VEHICLE WAS OFF, WE WERE ASLEEP, NOBODY HAD ACCESS TO INTERIOR OF VEHICLE. A PHONE CHARGER WAS PLUGGED IN, POSSIBLY ANOTHER CHARGER AS WELL.WE CONTACTED GM TO FILE A WARRANTY CLAIM. IT WAS DENIED, ACCORDING TO YVETTE YOUNG BECAUSE "GM COULD NOT DETERMINE THE CAUSE OF THE FIRE SO IT IS NOT OUR PROBLEM." GM DID THREE INVESTIGATIONS, ONE BY THE ADJUSTER, AND TWO MORE THAT INCLUDED A "DESTRUCTIVE INSPECTION." THIS WAS A TWO AND A HALF MONTH PROCESS. WE WERE NOTIFIED BY PHONE THAT THE CLAIM WAS DENIED AND THE LETTER THAT ARRIVED LAST WEEK IS ATTACHED. WE DON'T SMOKE, DID NOT HAVE ANYTHING COMBUSTIBLE IN OR NEAR THE AREA AND ARE CONCERNED THAT THE FIRE WAS RELATED TO THE CHARGERS. SOMETHING IN THAT VEHICLE ALLOWED THE CHARGERS TO OVERHEAT EVEN THOUGH THE TRUCK WAS OFF, IN OUR OPINION. OUR CONCERN IS THAT IF THIS HAD BEEN IN A GARAGE OR HAD PEOPLE BEEN IN THE VEHICLE, LIVES COULD HAVE BEEN LOST. VEHICLE HAD 12,000 MILES ON IT.PURCHASED NEW, NO OBVIOUS CAUSE FOR THIS EVENT. EVENT OCCURRED AT BAY POINT IN PANAMA CITY, FLORIDA.