Electrical System Problems of GMC Sierra 3500 - part 1

Randomly when the truck is turned on, the turn signals will stop working, no noise, nothing. When this happens, the infotainment system also stops working. It is unsafe to be driving and not knowing if your signals are working or not. This has been happening since the truck was purchased from the dealer.

See all problems of the 2025 GMC Sierra 3500 🔎.

This 2024 GMC sierra heavy duty has experienced a continuous pattern of major mechanical and electrical failures since early ownership. The vehicle required a complete engine replacement under warranty at approximately 43,626 miles. Since that time, the vehicle has continued to experience repeated injector failures, control module faults, communication errors, and voltage-related system issues. Current diagnostic codes indicate multiple simultaneous failures including ignition relay feedback circuits, control module power faults, gateway communication loss, brake system communication faults, and battery voltage circuit errors. The dealership has diagnosed a power distribution / fuse block failure at approximately 79,000 miles. These electrical failures affect multiple vehicle systems and raise concerns regarding reliability and potential safety risks due to loss of communication between control modules and possible braking system interaction. The vehicle has been in the dealership numerous times for repairs including engine replacement, injector replacement, control module reprogramming, and electrical diagnostics. I am submitting this complaint due to concern over a potential systemic electrical defect and ongoing reliability issues.

See all problems of the 2024 GMC Sierra 3500 🔎.

Driving on the freeway going approx 70 mph and the abs warning light, and stabilitrak warning light suddenly turned on. I’m sure you can imagine how panicked I was going that fast on the freeway and having my brake warnings suddenly turn on. Especially with my entire family in the vehicle with me at the time. Could feel a difference when I was attempting to brake and exit the freeway. Had to apply tons of pressure to get the brake pedal to engage. The cruise control would no longer work, and the trailer brake monitoring system also began flashing. Truck has been to 2 GMC dealerships the abs module was replaced made it approximately 2 miles and it came back on. Truck is currently waiting for another part to attempt to fix the problem. Truck has 86,000 miles on it.

See all problems of the 2018 GMC Sierra 3500 🔎.

The brake controller on trucks error out while towing. Shuts brakes off. Not a good thing towing 16,000lbs down hill. Almost accident. Destroyed my truck brakes and warped rotors. The controller checks the house battery on trailer and if not in range shuts brakes off. The brake towing screen in truck states all is good but there is this tiny little light at gain adjust location that goes off and you do not have brakes but yet your screen states you do. Bad deal.

See all problems of the 2023 GMC Sierra 3500 🔎.

The transmission control module stopped working leaving the vehicle unable to be driven and no part support from GMC/allison and part is backordered with no eta. There are reports the module becomes defective due to its placement near engine heat. There should be a recall for this issue. Many people are experiencing this issue.

See all problems of the 2010 GMC Sierra 3500 🔎.

The contact owns a 2021 GMC Sierra 3500. The contact stated that while his wife had the vehicle idling with the rear defroster activated, shortly afterwards, she observed smoke coming from the plastic on the rear sliding window. After a visual inspection, the contact's wife observed that the plastic was melting, prompting her to deactivate the rear defroster. No warning lights were illuminated. The vehicle was taken to the dealer, who was unable to determine the cause of the failure. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 26,000.

See all problems of the 2021 GMC Sierra 3500 🔎.

Driving down the road and I got a service trailer brake code pop up and would not go away and kept dinging it is very distracting and sometimes causes the trailer brakes to malfunction.

See all problems of the 2016 GMC Sierra 3500 🔎.

Trailer brake system connection warning intermittent when towing it will say trailer not connected, while still having a secure 7 pin connection. This causes me to loose trailer brakes. My camper is nearly 14,000 lbs. Very dangerous situation. Happened since new. Was into / complained to gm service dept over 6 times.

See all problems of the 2017 GMC Sierra 3500 🔎.

Weekly you will start the truck and have no audio of any kind. No blinker noises no collision warning noises, no radio, no on star noise. No sound at all and sound will never come back on until you turn truck off and wait 20 mins. GMC says it's a known software issue, but this has been going on since I bought the truck brand new back is April of 2025. I live in a hands free while driving state when it's come to cell phone use and can't even take a call with no audio of any kind. I don't see how GMC can say this isn't a safety issue.

Battery would not hold charge and would need jump start. Transmission would not stay in gear while towing trailer and would only go to 5th or 6th gear and would jerk out of gear and oil temperatures would go to 225 degrees. Erratically shifting and while driving with cruise control stop with out warning.

My truck has the shift to park issue and won’t allow me to shut the vehicle ignition off and I cannot shut the vehicle ignition off and it is unsafe and keeps me trapped in my vehicle. I have noticed that it is a common issue and recall on many GMC trucks and I took it to the dealership and they are not wanting to cover it with my two warranties I have on the truck and my vehicle is unsafe. I cannot park the vehicle and shut it off. When I go to put the truck in park on shift column lever, it says shift to park on dash and I turn it on and move shifter to drive and neutral and the vehicle still won’t allow me to shut it off and it shows the same issue. . The issue just began out of no where.

The contact owns a 2024 GMC Sierra 3500. The contact stated that the exterior lights of the vehicle were flashing erratically, and the tailgate was opening unintendedly. The contact stated that while driving at various speeds, the vehicle experienced erratic transmission shifts, and the vehicle was jerking and made an abnormal clunking sound. The check engine warning light was illuminated. The contact pulled over to a truck stop and parked the vehicle. The contact stated that the battery became fully drained while parked with the windows rolled down in snowy weather. The contact stated that after waiting 6 hours for aaa to arrive, the vehicle jump-started. The contact stated that the battery had drained on several occasions. The vehicle was taken to the dealer, where it was diagnosed that the two batteries needed to be replaced. The vehicle was repaired; however, the failure persisted, and the vehicle overheated while driving. The contact stated that GMC onstar was contacted and informed the contact that diagnostic trouble codes related to the transmissions were retrieved. The vehicle was taken to another dealer weston Buick GMC (22555 se stark st, gresham, or 97030) to be diagnosed. The vehicle was being diagnosed. The vehicle was not repaired and remained out of the contact's state of residence. The contact related the failure to an unknown recall; however, the VIN was not included. The manufacturer was notified of the failure and covered vehicle rental expenses that allowed the contact to return to their residence. The contact stated that the vehicle was used for load transportation, and the failure had caused both the contact and her husband to be stranded while delivering loads, which caused lodging expenses and loss of wages. The failure mileage was unknown.

The gm n242454440 “collision rear wheel lock up from transmission valve failure” was performed. The recall rendered the electrical charging system inoperable. Gm engineering has been working on the vehicle for more than one month and recently determined that the recall software does not work properly with all vehicles. My truck is being returned to me without the recall being performed. Accordingly the safety hazard associated with rear wheel lockup has not been addressed and cannot be addressed at this time. Presumably gm will develop software in the future to address the safety condition. Meanwhile the safety hazard remains unaddressed for my vehicle and an unknown number others. Reference riverview Chevrolet GMC repair order 894074.

See all problems of the 2022 GMC Sierra 3500 🔎.

• what component or system failed or malfunctioned, and is it available for inspection upon request? the issue appears to be with the gear shifter assembly and/or park position sensor within the power train system. The vehicle fails to detect that it is in “park,” even when the gear lever is physically in the park position. Yes, the vehicle and component are available for inspection upon request. ? • how was your safety or the safety of others put at risk? this malfunction prevents the vehicle from shutting off properly and displays a “shift to park” message even when parked. This creates a risk of the vehicle rolling away if the parking brake is not engaged and prevents secure shutdown, potentially draining the battery or creating confusion in an emergency. It compromises both driver and public safety. ? • has the problem been reproduced or confirmed by a dealer or independent service center? yes, the issue was reproduced and acknowledged by a certified GMC dealership service department. They noted it is a known issue affecting other gm vehicles but stated there is no open recall or warranty extension currently available for my specific model. ? • has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? the vehicle has only been inspected by a GMC-certified dealership. No inspection has been conducted by the manufacturer, police, or insurance representatives at this time. ? • were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? yes, a “shift to park” message appears on the dash even when the shifter is correctly placed in the park position. This message began appearing intermittently and has now become a consistent issue over the past few weeks.

Car will not turn off and will display "shift to park". Similar recall on other models. This has gotten worse and happens most of the time now.

On at least 5 occasions, my inner tailgate has released itself and gone down during motion. This has been uncommanded. It appears gm has a recall for this but it does not include my truck. The dealership that looked into it agrees this is likely the same issue and gm should include it in the recall.

I purchased my vehicle in 2019. Since then, I have had several issues. I've had to replace the coolant reservoir, def heater/pump and twice changed the number 8 injector plug. The warning light came on just after the warranty went out. The code reader read the ambient sensor and no sensor.

See all problems of the 2019 GMC Sierra 3500 🔎.

On multiple occasions, the vehicle has suffered from a severe computer failure. This results in the driver information center losing all data, the climate system shutting down, loss of all driver assistance features, loss of computer based safety systems, and prevents the vehicle from shutting down or being restarted until the batteries are disconnected. This results in the driver having no information about speed or engine parameters while driving. This error has not been reproducible by the dealer however they were able to assess it while one error occurred while driving by them. Their diagnostics show a complete failure of all 3 data buses and failure of the serial data gateway. Troubleshooting thus far has been unsuccessful. During the failure, all errors possible are lit on the warning lamps and the driver information center displays warnings for all vehicle modules. The attached photo was taken during one of the events after pulling off the freeway. While traveling at freeway speeds, the information on the screen was the same indicating no speed. This presents numerous safety risks.

The contact owns a 2018 GMC Sierra 3500. The contact stated while driving at various speeds, several unknown warning lights illuminated on the instrument panel. The contact pulled over to the shoulder of the roadway to restart the vehicle. After the vehicle was restarted, the vehicle hesitated to stop while depressing the brake pedal. The local dealer was contacted, but the vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 53,800.

Encountering trailer brake issue where the brakes on our 5th wheel do not activate via the GMC trailer brake control module. Have just had it replaced and still experiencing the same issue where it posts an alert on the screen multiple times and does not activate brakes on trailer. This is a widely known issue with GMC trucks and the trailer brake that has been outstanding for over 3 years now and is a safety issue as there doesn't appear to be a fix from any dealerships or GMC. GMC has not taking adequate accountability for this issue. I'm looking at putting together a class action lawsuit with several other customers having the same issue. We are fed up with the inaction and falsely advertised towing package as we are unable to safely tow anything with their trucks.

Intermittent loss of trailer brake function. While traveling and towing a RV trailer with electric brakes, receive a dashboard alert that trailer brakes have been disconnected. This has occurred since vehicle was new. Trailer brake system has been inspected and trailer is not the issue. Took truck to GMC dealer. They are well aware of common issue with GMC owners. GMC issued a safety bulletin 6+ months ago to dealers to replace the integrated trailer brake controller (rpo code jl1). Per reports that has not solved the issue. My truck did not fall into that safety bulletin. Customer satisfaction program number n232414840 says, with the brake issues caused by a potential fault in which voltage feedback occurs. This is a dangerous safety issue.

When carrying the electronic key in my pocket the vehicle will lock/unlock presumably due to the remote contacting other items in the pocket. I have owned well over a dozen gm vehicles and never had this issue. I believe the remote design has the lock/unlock buttons too proud of the surrounding surface.

Multiple instances of diesel engine emissions system parts and software failure. While driving, towing or not, the dic would randomly display a message that the def level is low and reduced speed will occur in x-amount of miles and that mileage would then begin a visible countdown on the dic, sometimes much more quickly than the actual speed I was traveling. In other words, it might at first state 500 miles remaining, but then be counting down from 500 miles by one mile per second of time, or faster. Each instance, I would park and attempt to refill the def tank, only to discover that the tank is already full or near full. My truck’s def tank has now been replaced twice under warranty with the latest tank being installed at only 35,460 miles on the odometer. During the latest replacement, the technician also diagnosed and replaced the electrical wiring harness related to the def tank, stating that one of the connector pins was not reading the required voltage. There was also a faulty diesel particulate sensor that was replaced under warranty. This emissions system is problematic, and it is unsafe to due to the drive ability restrictions it imposes due to faulty software and equipment. I use my truck to tow, and it would make for a very unsafe condition to have my vehicle’s speed become limited as if the vehicle ran out of fuel. Mountain grades. Two-lane highways. Passing through bad neighborhoods. Driving in uninhabited areas, sometimes late at night. Family of 6 in the vehicle. Unacceptable. General motors corp. Must create a permanent and fail-safe fix for this emissions system and implement the parts. The emissions system warranty should be extended from 80k miles to lifetime to cover the vehicles affected.

The in cab brake controller does not work with electric over hydraulic trailer brakes. In my research to diagnose and fix the problem I find out GMC has known about this for years and has done nothing to correct. I pulled code c1114 and GMC issued a bulletin for part number (k58-036-00) which I purchased and still did not correct this issue. In short there are many 3500 trucks out there running with no trailer brakes. Here is the worst of this problem. If brakes are tested at a stop they appear to work perfectly however once driving this is when the error code is delivered to the truck so the brakes work at a stop when not needed and do not work under driving when they are needed. GMC has ignored this for years and after spending more of my hard earned money for a fix that did not fix the problem. Below I had to choose a date however this has been an issue since first purchase December 5th 2023 to present.

While driving the truck began switching between towing, normal, and off-road driving modes. Lights were flickering and various messages were being displayed on the dash cluster screen. After parking truck and shutting it off all of the lights were flickering and I was unable to start the truck. Charging the batteries did nothing nor was I able to jumpstart the truck with another diesel. After repairs for these issues, at some point the odometer reset and while likely not certain it reset to zero. Gm has no way of knowing when it reset and how many miles were driven between leaving the dealership and the reset leaving me with a truck set to the best guess mileage. I am being told this was a software bug and having experienced another software bug when I had the recall to enable seat warmers where the keyfobs would not work in any way I have serious concerns about the quality and safety of the software on these trucks.

We’ve had issues with the electrical system/brake lights when we hook any trailer (horse/boat/utility) to the truck. One issue is that the system shows unconnected and the trailer lights blink or do not work. We’ve brought this in to the dealer 3 times and they have yet to resolve the issue. The other issue of melted plastic on our rear sliding mirror. It just appeared one day, possible after using the rear defog button. We took it to the dealer and they also do not know what is the issue. We found several other blogs where owners have had the same issue. This is a newer vehicle, and we live in southern California where the temperature is mild. It just appeared one day. We are concerned this is a safety issue with the electrical system melting the plastic and possibly causing a fire. Here is a link to a blog: [xxx] lastly, this vehicle was advertised as having adaptive cruise and it does not have the capability (chip) to do so. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

Vehicle caught fire minutes after remote starting. Fire appears to have started on firewall on the left side. We were about to take our kids to school vehicle could have easily caught our house and other property on fire. We did have the check engine light come on occasionally but it would always turn back off, vehicle only had about 12000 miles. Also none of the outlets inside the vehicle never worked.

Hello, I purchased my 2024 GMC 3500 at4 seirra late October 2023. Since the purchase date, I have been informed by motorist while at intersections my tailgate was down. I thought I was doing something wrong. On 3/3/2024 I was preparing to wash my truck and noticed my front amber lights were on surrounding my headlights. The vehicle was off, and my keys were in the house. Then my tailgate opener activated on at least 10 - 12 times. The tonneau cover is tight so the tailgate can need assistance opening. Nevertheless, the tailgate has opened on a number of occasions and my two front amber lights came on at least once. I reported this to my dealership on [xxx]. They said my truck has not been recalled yet but to watch this and if it progresses to call them. I noticed a small dent in the top rail of the tailgate on [xxx]. I have yet to put anything in the bed of the truck or even install a hitch in the receiver. I believe the tailgate had to be bumped when it was down by another vehicle, and this is absolutely related to the tailgate malfunction. Since I haven't used the bed of the truck. Moreover, I feel GMC should be held responsible for the repair or replacement of my tailgate. Regards, [xxx] information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

Vehicle will not start due to known gm issues. This failure left my family stranded in cold dark unsafe area once already. If we were in the flow of traffic or had to leave an area immediately we would have been unable too. Known gm issue, engine fault code p12a6 fault code. Bulletin: pip5719a discusses this issue. I am being told by the dealer there is a newer bulletin which advises ecm update. Gm dealer is stating ecm software upgrade is required to resolve at owners expense. Owner is responsible for diagnostic fee in addition to repair costs. If the issue is not resolved vehicle may continue to experience starting failure and or other electrical problems. The night the vehicle left us stranded instrumentation was erratic and not reading properly on the instrument cluster. Very unsafe and gm should reach out to customers to inform them a software update is needed and it should not be at the expense to the consumer if the consumer is out of the bumper to bumper warranty.

See all problems of the 2020 GMC Sierra 3500 🔎.

There are 2 issues with this vehicle: #1) the rear window defrost causes an electrical issue that melted the plastic on our rear sliding window. Dealer claims we put something hot against the window but we did not. This appeared after we used the rear defrost. Several other owners have complained about this as well. #2) the vehicle is advertised as having adaptive cruise but it does not have this feature.

The fan for the heater doesnt work on all speeds properly, stopped working entirely.

See all problems of the 2004 GMC Sierra 3500 🔎.

My 2011 fmc Sierra 3500 drw denali suffered a failure of the transmission control module (tcm). I could barely move the vehicle and almost got into an accident merging into traffic. Forward and reverse was affected. The transmission reverts to top gear after the failure, and makes driving very difficult. There was no warning for this failure luckily I was minutes from my dealership. This problem could be bad.

See all problems of the 2011 GMC Sierra 3500 🔎.

Service trailer braking system. Faulty control in the dash. Known issue per mechanic but no recall issued. Safety issue as trailer brake may not function properly when towing as a result.

Various warning lights are coming on sincve I purchased this vehicle, such as abs, engine power reduced, oil changing service, service engine light, service trailer brake system, wheel tracking, service esc, passing gear cuts out. My vehicle has been in the shop many times and is in the shop now. I have a deep concerned for the safety performance of this vehicle for myself and my family.

Plugged in engine block heater and the car erupted in flames. Total loss.