2025 MERCEDES-BENZ GLC 300 Complaints

To the Office of Defects Investigation National Highway Traffic Safety Administration I am submitting this complaint to formally report a serious and recurring safety defect involving the automatic braking and collision detection systems in our Mercedes-Benz GLC. License Plate: 9RHN710 Dealer Servicing Vehicle: Mercedes-Benz of Stevens Creek (AutoNation), San Jose, California The vehicle has repeatedly experienced unexpected and unprovoked braking events, including situations where the automatic braking system engages despite there being no vehicles, pedestrians, or visible obstructions present. The issues observed include: • Sudden automatic braking activation without obstruction • Unexpected vehicle deceleration during normal driving conditions • Repeated dashboard alerts indicating “Speed Severely Restricted” • Repeated Attention Assist / “Coffee Break” warnings during normal local driving • Sudden brake engagement when parking, accompanied by a loud mechanical noise These events create a dangerous driving condition, as unexpected braking could lead to a rear-end collision from vehicles traveling behind the driver. During one incident, the abrupt braking caused a severe jolt to the driver, resulting in whiplash symptoms that required medical evaluation and MRI imaging, which identified cervical strain. The vehicle has been brought to the authorized dealership multiple times for inspection and repair attempts. However: • The dealership has not been able to diagnose or repair the issue • Service visits have largely been documented as general inspections • No ADAS (Advanced Driver Assistance Systems) diagnostic or calibration report has been provided, despite the fact that the malfunction appears directly related to radar, camera, or collision prevention systems. We respectfully request that the Office of Defects Investigation review this complaint and determine whether further investigation into this issue is warranted.

The component that repeatedly fails is the vehicle’s electronic display/infotainment system (dual digital screens/MBUX system) and potentially related electrical components in my 2025 Mercedes-Benz GLC 300 4MATIC. The system has malfunctioned six (6) separate times since I purchased the vehicle new in May 2025. When the malfunction occurs, both display screens suddenly go completely black and become inoperable while the vehicle is running. During these failures, the vehicle also produces a repetitive clicking sound from the dashboard area while the screens are off. The most serious incident occurred on February 17, 2026, when the screens shut down while I was driving and I detected a burning electrical smell inside the vehicle. This raised significant concerns about a possible electrical malfunction or fire risk. The digital display system provides critical driving information, including vehicle settings, safety alerts, and operational controls. When the screens shut down, the driver loses access to important vehicle information and control functions, which creates a potential safety hazard while operating the vehicle. This issue has been reproduced multiple times and the vehicle has been taken to Mercedes-Benz of Jackson, Mississippi for inspection and repair attempts on several occasions. The dealership has attempted repairs and indicated that they have opened a case with the Mercedes-Benz manufacturing department regarding the recurring electrical issue. Due to the repeated electrical failures, clicking sounds from the dashboard area, and the burning electrical odor detected while the vehicle was in operation, I am concerned that this issue may indicate a serious electrical defect that could potentially lead to overheating or fire. The malfunction occurs while the vehicle is being driven, which places the driver and passengers at risk. Because the display system repeatedly shuts down and the issue has occurred multiple times despite dealer inspections and repair

BOTH DASHBOARD SCREENS WENT DARK AND REMAINED SO THROUGH 5 CYCLES OF STARTING THE CAR. HAD NO OPERATING INFORMATION WHATSOEVER. TOLD BY DEALER THAT MANY 2025 GLC-300'S ARE EXPERIENCING THE SAME PROBLEM.

The instrument panel behind the steering wheel has gone totally dark. This issue happened about a month ago but resolved itself somehow. Issue happened again and will not correct itself. Took vehicle to dealer and they could not resolve issue with software update. Upon researching the MBWorld.org user forum I noticed this may be a wide spread issue. With a dark/blank instrument panel you cannot know your speed, fuel level, or what gear you have placed the car in. My technician even indicated he has seen this issue on several 2025 MB models.

The infotainment and instrument panel screens blacked out after the vehicle was started a few miles away from our home. I was unable to see the speedometer while driving back home. This was the first time that this has happened to us. After a Google search of Mercedes Benz 2025 GLC 300, this event appears to be fairly common.

When I entered my vehicle after it was washed at the Mercedes-Benz service location, I pressed Memory 1 button and the seat returned to my normal position. Without any further input, I started the engine, and the driver's seat automatically moved backward by itself. When I readjusted the seat and shifted into Drive, it continued moving rearward. As the seat moved backward, my feet could no longer reach the brake pedal. At the same time, the car began to move forward, and I lost control of the vehicle, resulting in a collision that damaged the right side doors. This malfunction occurred suddenly and without any warning lights or messages. The seat moved by itself twice-once when the engine started and again when I shifted into Drive. The issue appears to be related to the seat's electrical control system or memory setting malfunction. The dealership has inspected the vehicle but was unable to determine the cause of the problem. I am deeply concerned that this may happen again and could cause a serious injury or major traffic accident. The vehicle has approximately 2200 miles and was purchased new in March 2025. I am requesting a formal investigation to determine the cause of this automatic seat movement and whether other vehicles of the same model are affected.

The entire main console display AND the digital instrument cluster screen have completely frozen. Additionally, the gas gauge for how much fuel is in the vehicle is nowhere to be found. Temperature touch controls (no physical option), volume, car settings (which can adjust safety features, multimedia features, accessibility features), etc. are all completely unavailable and unable to use. For example, if the defrost option was on which defaults to full blast heat, I would’ve unable to turn it off. The only information that is properly updating is MPH, headlamp status, time, Emerfency brake, Gear, and outside temperature. RPMs cannot be seen. Some of the pictures attached show that I’ve been on a phone call for 3.5 hours. I’m not.

The brakes did not function at all. Upon trying to brake, the brake pedal was hard and the car would not stop. The car went into s storefront where the cashier is located and could have resulted in serious injury or death to anyone waiting to pay at the store. The forward collision alarm did not sound, the dashboard indicator for an impending forward collision did not illuminated. The car did not slow down or stop to avoid the collision. The car is currently at the body shop.

The contact owns a 2025 Mercedes-Benz GLC300. The contact stated that while driving approximately 30 MPH, there was an abnormal grinding sound coming from the vehicle. The contact stated that the brake assist suddenly activated and the vehicle came to an abrupt stop, causing the seat belt to immediately retract and lock. The contact was slightly jerked from the abrupt stop. The contact stated that a warning light with a red triangle with an image of a crash in the center was illuminated. The contact stated that after starting the vehicle, the infotainment center and the instrument panel were completely black. The vehicle was restarted several times before both systems started operating as needed. The failure occurred twice; however, the second time, the contact had to turn off and restart the vehicle for approximately an hour before the infotainment center and instrument panel became operational. The vehicle was taken to the dealer, who performed a software update for the infotainment center. After the software update was completed, the contact became aware there were other electrical systems that failed intermittently, including the voice activation system. The vehicle was returned to the dealer and the contact was informed that the front driver’s and passenger’s sides sensors were too low and there was no reason for the notification to become activated. The vehicle was not diagnosed or repaired. The manufacturer was informed of the failure, and a case was opened. The failure mileage was approximately 2,000.

The driver’s seat automatically adjusted while the vehicle was in drive, causing me to lose the ability to reach the pedals and almost resulting in a collision. While driving my 2025 Mercedes-Benz GLC 300 4MATIC with my children in the car, I stopped at a stop sign when the driver’s seat suddenly began adjusting itself backward. My husband also drives this vehicle, and because I had not logged into my driver profile, the car began moving the seat and controls to his saved position, while the car was in drive. The seat moved so far back that I could not reach the pedals. I lost control of the vehicle while another car was turning into my lane. The only way I avoided an accident was by quickly putting the car into park before the seat adjustment completed. This was a terrifying and dangerous situation. Automatic seat adjustments should never be allowed while the vehicle is in motion or in drive. This design flaw puts drivers, passengers, and surrounding traffic at risk of serious injury or death