Electrical System Problems of GMC Sierra 2500 - part 1

About 2-3 months ago I had a battery swell up and start smoking and making an awful smell in my truck. I took it to dealership and was informed that I needed a new battery and it was not covered under bumper to bumper warranty or my extended warranty which I thought was ludicrous. The truck is 18 months old. It does have 50,000 miles but I have yet to see one that isn’t at least prorated for five years. So fast forward to today and the other battery starts doing the same thing except this time my lights are going crazy. Brights on and off and on and off. I get back to my camp and the battery and wiring is smoking like crazy. I towed it to the shop. It’s been in there two weeks and the only thing they tell me now is that I need 2 new batteries and that’s all they can do until I agree to pay for the other one that isn’t under warranty (because I already paid 300 to change 1st one it’s under warranty for 5 years). So I told them to do it. It’s been there two weeks and not a damn thing has been done. Not even installed a new battery. I know because I went yesterday and they couldn’t open my tailgate to get my tools out. Probably the last GMC I purchase.

See all problems of the 2024 GMC Sierra 2500 🔎.

The main tailgate will not go down or function properly and it says online there is a national recall for this, but does not come up when I search my vehicle. When I turn on my left turn signal the brights flash for no reason and this is a known major issue with the vehicles as well. The trucks computer is telling me low on coolant even though it is not that has already been fixed through a 3rd party warranty parking brake was stuck on when I bought the vehicle and had been for a long time you could tell and I had to pay over $1100 to fix it at gm. The Ford collision system does not work properly and the cameras will come on at certain times when they're not supposed to be and not come on when they are supposed to be.

See all problems of the 2020 GMC Sierra 2500 🔎.

My center console wires for the charging pad broke and shorted out causing wires to burn and short the whole system out.

See all problems of the 2019 GMC Sierra 2500 🔎.

The rear defroster massively overheated. It started heavily smoking and eventually exploded the rear windows. Only warning sign was the smoke which we noticed quickly because the windows were up. Had the windows been down we might not have noticed before a fire started. I'm taking it to a dealership now. This module also triggers on from a remote start. Extremely dangerous!!!.

After driving my truck, once I park and turn the truck off it will not shut down electronically due to an error on the dash display that reads “shift to park”. Sometimes I have to mess with the gear shifter when the truck is in park to get it to register that it is parked and shut down completely. It can take up to 15 minutes sometimes to shut down.

See all problems of the 2022 GMC Sierra 2500 🔎.

This vehicle exhibits the same failure described in NHTSA recall n232426400 — spontaneous unlatching after rain due to water intrusion into the exterior tailgate release switch. I’m requesting a goodwill replacement under gm bulletin # n232426400 as the failure mechanism and part are identical. It has caused brake failure and nearly killed me because of battery drain while driving. All american Chevrolet of midland texas is refusing to solve the problem and says no recall is available.

Led instrument cluster goes blank. No speedometer, no fuel gauge, oil gauge, nothing.

During a drive home, while in motion, the tailgate of the vehicle opened on its own. This has occurred after the recall to repair this issue was already performed. I know the tailgate was shut prior to the drive because I back into my parking spot and walk the sidewalk behind my truck prior to starting the vehicle.

After placing the vehicle in park and try to turn it off, I receive a message saying “shift to park”. The engine is off and in park, but the vehicle doesn’t recognize it as being in park so all of the electrical stays on. I started complaining about this to the dealerships before my warranty was up but they kept giving me the run around avoiding the fix and now that the warranty is expired they want to help me for a ridiculous fee. This issue happens randomly at least one day a week.

I was driving my 2022 GMC 2500 hd (not towing, just normal drive) after an oil change <900 miles ago and new brakes/rotors 3 days prior <100 miles (total mileage 81,000, serviced exclusively at GMC dealership) when the loss of power alert flashed on the screen. I was 2 miles from my destination, going approx 55mph, so I kept driving to destination, when the vehicle stalled in driveway. As I was scrolling through menus to see the alert I looked up and smoke and flames were coming out of the engine. I attempted to extinguish with a fire extinguisher I had with me, but it was no use. The entire engine was engulfed, melting out, tires and windshield exploded from heat etc. Total loss. Vehicle was inspected by insurance CO fire investigator, no origin confirmed due to extent of damage. Vehicle was offered to GMC for their inspection as it was partially under oem warranty and I had an extended warranty from dealership, which I also notified. Extended would not do anything without the vehicle at GMC and diagnosis, which again, there is no engine etc so not repairable. GMC was to be in contact with insurance CO. No status update received.

The manufacturer placed two 12v batteries to start the truck with one being located on the passenger side just in front of the cowl of the cab. The factory oem batteries are known to overheat when charging which is exactly what mine did and as the battery boils over with sulfuric acid, the acid is vaporized and ingested into the cabin. It’s a diesel so it’s common for me to take my dog in the rear crew cab with me and leave the engine running so the cabin will stay cool in the summer while I work my contractor job. When I let the engine idle with windows up and ac on the overcharged battery introduced the vaporized sulfuric acid into the cabin and rendered the interior deadly toxic. Luckily I was only gone from the truck for about 10 minutes but in this amount of time the acid was very bad and caused burns in my dogs throat and mine while driving home. I can only imagine if this scenario were to take place with kids left in the truck for many reasons to stay cool but could easily turn into a deadly situation. Please look into this before someone or some poor animal is fatally injured or killed.

I rely heavily on this vehicle for my business and within 1 year of ownership, the vehicle broke down on the highway allowing it to only run @ 30mph. After finally locating a dealer who could evaluate the vehicle in less than 1 week, I was informed that the part was unavailable and they indicated, "it could take 1 month or 3 months to receive. " following multiple conversations, I was forced to open a claim with gm customer care. While trying to get information, I was, at one point, told that "although the code indicates failed transmission control module, it doesn't happen all the time and if I wanted to drive it I could come and take it until the part arrives. " that really told me alot about how gm representatives view safety while when it happened, I was on interstate and nearly got trounced by oncoming heavy traffic while pulling an equipment trailer. After the case was handed off to several gm customer care representatives, I finally rec'd feedback including several email updates. I finally rec'd the vehicle back after 1 month and was informed that 1) would receive car payment from gm & 2) would receive additional compensation for lost work time while my vehicle was out of service (Jan 2024). Since that conversation, I did receive 1 car payment however, never heard back from alisa regarding "lost time". I have sent several emails to customer care asking for an update however, crickets. Furthermore, the car has returned to the shop for another warning to "shift vehicle to park" when it was in park. They told me its a electrical malfunction but they could not get the error to come up on test. I have a photo showing the error.

See all problems of the 2023 GMC Sierra 2500 🔎.

Shift to park message displayed while attempting to shut off engine after shifter was in the park position, accessory would not turn off even after driver door opened and could not leave vehicle.

Having issues with inner tailgate opening on its own and items falling out of bed/box onto road!.

Vehicle was parked in a school parking lot. Rear trailer harness and modules in back short circuited causing an electrical fire that expanded to the driver’s taillight rear bumper, and bed of truck.

024 GMC Sierra 2500 denali ultimate, which has suffered: •five catastrophic engine failures at highway speeds. •total brake failure, leaving the truck unable to stop. •severe electrical malfunctions, including flickering headlights at night. •retaliatory actions from general motors after I refused to waive my legal rights. I have documented proof, including gm’s own service records, emails, and a 7-minute recorded statement from gm’s highest-level technician, confirming that gm installed the wrong computer module (1500 series instead of the required 2500 series) in my truck. Additionally, I have evidence that gm executives instructed technicians to conduct diagnostics, take apart the engine, and reassemble it—but not repair the defect—after I refused to sign an affidavit waiving my rights. Due to these failures, I suffered a dislocated shoulder in one of the incidents, and my [xxx] daughter remains traumatized to this day. Given the immediate danger this defect poses to other GMC Sierra 2500 owners, I respectfully request that NHTSA open an investigation and consider issuing a recall before a tragedy occurs. 1. Engine failures since 3,000 miles – gm’s own work orders confirm issue since purchasing my 2024 GMC Sierra 2500 denali ultimate, I have experienced five catastrophic engine failures, all occurring while traveling at highway speeds (70 mph): •the truck suddenly lost power, dropping from 70 mph to 5-10 mph within seconds. •this created an immediate risk of being rear-ended or losing control on the highway. •gm’s own service records confirm that my engine issues began at just 3,000 miles. •gm dealerships misdiagnosed the issue four times, returning my truck to me in an unsafe condition. •the real cause was only identified after the fifth failure, when a gm-certified head technician finally determined that gm had installed the wrong computer module (1500 series instead of 2500 series). This means that for months, gm knew my vehicle w information redacted pursuant to the freedom of information act (foia.

The side mirrors have spider cracked from some type of electrical issue. This is the 2nd time this happened and it burns both mirrors at the same time. The mirrors become unusable and it appears the dealer replaced them under warranty the first time and the second time they said it is out of warranty so I had to pay out of pocket.

When I am driving in town I have an indication message that comes up and says engine power reduced.

See all problems of the 2009 GMC Sierra 2500 🔎.

When I’m in reverse the up the cameras turn off. On one incident I was backing up and the camera turned off causing me to back up into the wall of my house.

See all problems of the 2021 GMC Sierra 2500 🔎.

Trailering a trailer with electric brakes. The vehicle intermittently reports connection issues where the brakes are temporarily disabled however the trailer lights are not effected. This leads to a period of time where there are no brakes on the trailer. Pretty confident we have eliminated the trailer as causing the issue.

I leased this vehicle on may 17, 2024, expecting it to function as intended. Instead, within months, it suffered recurring and escalating failures that have rendered it unsafe and unusable. January 7, 2025, I brought the truck to gates GMC for routine service and reported that it had lunged forward by approximately 2 to 2. 5 feet while shifting into park. Additionally, it exhibited irregular acceleration and rough down shifting in lower gears. I also communicated the check engine light has come on and gone off on the dashboard over the past week a few times without receiving any information on the app. At this January 7th visit, gm performed recall n242435631, supposedly addressing a known battery drain defect that caused total vehicle shutdowns. On January 24, 2025, I started the truck and was immediately overwhelmed by an intense chemical odor coming through the ventilation system. January 31 – February 1, 2025 – erratic engine warning lights & diagnostic failures on January 31, 2025, at 5:28 pm, on this key cycle the check engine light illuminated but failed to register in the gm app. On the next key cycle, the warning disappeared. The following morning, February 1, 2025, at 10:26 am, the check engine light appeared on the first key cycle before disappearing on the second key cycle. The onboard diagnostics system failed to log or retain these warnings. On February 7, 2025, the vehicle suffered a complete electrical failure. No electronic function whatsoever. Roadside assistance attempted to jump-start the truck using a high-powered jump pack, but it remained inoperable. A Ford super duty and jump pack were needed to force start the truck. February 10, 2025 the truck suffered another total electrical failure and required towing to gates GMC. The app indicated the brake system, anti-lock braking system, emissions system (specifically the exhaust system), and power train requiring service. My truck is at gates GMC and was drawing 90 milliamps opposed to 40.

On 11/21/24 noticed passenger headlight day light running light flickering. On 11/22/24 right turn indicator intermittent fast blink, dash message stated turn indicator failure. Once home, inspected passenger headlight assembly. Found drl, turn signal, and low and high beam head lights were inoperative. On 11/25/24 went to GMC dealer/service. Staff seemed aware of issues and stated they are common, that they carry the $1,400 sealed assebly in stock. Vehicle is 4 months over warranty, but only has 29,000 miles. There is no visible damage to the assembly, but there is visible condensation inside the lens. Gm has a published service bulletin, 01-08-42-001p, that specifically addresses this issue for my vehicle. The earliest date the issue could be diagnosed/service date is 12/10/24. A complete failure of this non-servicable headlight assembly is an absolute safety issue. Decreased daytime visability with the loss of one of two daytime running lights, the lose of the front turn indicator to alert other drivers of my intentions, the lose of a set of low and high beam headlights. As mentioned, there assembies are a sealed led light assembly. If any one of these lights fail, the only remedy is the replacement of the entire unit with a $1,400 part. Gm has had multiple recalls of this same issue among their vehicle, but continues to produce the same failing pieces.

Smog system check and engan warning light keeps come on.

When it rains, there are puddles of water on the passenger side! cannot figure out how the water is getting in. . My concern is of a potential electrical short/ fire / failure of a system that doesn’t allow me to operate the vehicle safely! possibly, affecting other functions of the vehicle during operation!.

Vehicle was last driven on June 23 2024 and parked in my driveway. On the evening of June 29 2024 my horn was blowing in my truck at around 10:30. While I was walking out to the vehicle it was in flames. The fire started from what I understand on the driver’s side behind the dash. Luckily no one was in the vehicle when it happened.

Brake control module disconnects trailer brakes while towing. Apparently a known issue with trailers equipped with solar battery chargers which have higher charge than vehicle battery. It feeds back into the trailer brake power module causing it to shut down. The vehicle has an integrated trailer brake controller as it is specifically designed with primary function as a tow vehicle. Shutting down the integrated trailer brake controller results in loss of trailer brakes. Not having trailer brakes is critically dangerous. Gm has issued a TSB #23-na-149 specifically addressing this known defect. Unfortunately, gm refuses to authorize its service technicians to replace the defective brake controller unless they experience the defect personally - the policy is to disbelieve the customer with the defective vehicle. Effectively, this requires providing the trailer to the service tech to drive around until the brakes fail, thus creating another dangerous situation for a tech who may or may not have experience driving vehicles over 50’ in length. Thus, it would appear the best remedy is to enforce a recall to replace the defective brake controller before someone is harm by loss of brakes, since gm requires its techs to encounter a loss of brakes before authorization of replacement of the known defective unit. This happened over 25 times during a trip last week. This fact situation reveals why your administration actually exists - to protect the public from harm.

The contact owns a 2024 GMC Sierra 2500. The contact stated that the vehicle had failed to start on several occasions. The vehicle was taken to the dealer, where it was diagnosed with low voltage and electrical failures. The dealer replaced the two batteries; however, the failure recurred. The dealer then replaced one of the batteries; however, the failure persisted. The vehicle was towed to the dealer. The vehicle was not repaired. The manufacturer was notified of the failure, and the contact requested buyback assistance, but no assistance was provided. A case was filed. The failure mileage was approximately 22,000.

Electric trailer brake control modular is malfunctioning on my 2015 GMC sierra denali 3500. Multiple of sources told me this is a common problem with this generation of GMC.

See all problems of the 2015 GMC Sierra 2500 🔎.

Water intrusion resulted in the tailgate inadvertently unlatching while the vehicle is in park multiple times while being washed. This apparently happened throughout the night, assuming voltage was being used to send open signal, which resulted in drained battery. In my case my VIN is not on the recall that is out on GMC for tailgate issue. And dealership determined there is a pinch in tailgate speaker harness that is causing the issue. Which I’m sure that harness is tied into tailgate latch harness. What needs to be addressed in this recall is for the two drain holes on top of tailgate to be somehow sealed. Drain holes are directly above tailgate latch and harnesses which is the main concern in this problem.

The contact owns a 2024 GMC Sierra 2500. The contact stated while driving at an undisclosed speed, the sun struck the solar panel used to charge the battery, and the surge from the battery entered the pigtail going through the truck, and disconnected the brake module, causing it to become disengaged from vehicle. The contact took the vehicle to the camper and vehicle dealer who both stated there was no issue for concern. The vehicle was not repaired. The manufacturer for the camper and the vehicle were made aware of the issue. The vehicle failure mileage was 8,000.

While driving both drivers and passenger side blind spot warning lights flash on and off when no cars are near. The problem is worse at night when pulling a trailer. The lights sometimes stay on or starting flashing on both side causing a significant distraction.

The harness that hooks to bumper plug for trailer lighting is not completely water tight. Allows water in and creates buildup that weakens the connection as well as allows the plug wire connection to snap out and push out from the pin. Further inspection it was causing a short in the system. I attempted to clean and put some-electric grease on the plug to help clean it but then relaized 3 pins were broken and pushed back.

I drove from California to ohio after I bought the truck, I noticed that when stopping to get gas my tailgate was open without me touching it. I drove with cameras showing the truck bed to see what happened and I watched it do it again while driving the vehicle, it just opened on its own while driving. The incident happened again once I was back in ohio when I had my trailor hooked up and it cause the tailgate to collide with the trailor tongue and dented the whole top of the tailgate. 3.

While driving the entire dash cluster (speed,rpm etc) turns off entirely, reloads as if truck is just starting with all lights coming off and on, needles cycling max/min. Unable to recreate on command, multiple others reported same issue with no cause/cure listed.

Headlights and turn signals failed. Flickering of various lights (daytime running lamp, low beam, high beam, turn signals) followed by total failure. 3700 dollar repair at dealer to replace both headlamp assemblies. Barely over miles of warranty, but still in the 3 year warranty time period. Not having forward lighting is of course a major safety issue. Vehicle should be recalled. Many others are having the issue.