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What 36 owners told NHTSA about the 2021 Mercedes-benz GLS

These are the actual owner complaints behind this car’s reliability verdict, filed with the federal government, unedited. They’re unverified reports, not confirmed defects: read them as leads for your pre-purchase inspection, not a diagnosis.

All (36)Crash / fire / injury (5)Electrical system (16)Engine (4)Driver assistance (3)Lane Departure (3)Fuel system (2)Seats (2)Visibility & wipers (2)Airbags (1)Body & structure (1)Seat belts (1)

2 of 36 complaints match · Electrical system · crash/fire/injury only · clear filters

May 16, 2025Electrical systemSeatsFire

On [XXX], I was heading home from work traveling [XXX] on [XXX] through Atlanta's usual heavy traffic. I smelled smoke inside my car and saw fire flames coming from under my passenger seat. My initial reaction was to try to put the fire out with my hat without burning myself. Also, I had to try to navigate across multiple lanes of traffic without hitting anyone and avoiding anyone hitting me. Safely, i reached the side of the interstate and exited the vehicle. As I stood from afar watching my vehicle burn; the reality sat it that a few minutes earlier that could have been me trapped burning inside, injured or even death because something had failed in my vehicle. Later, when I finally arrived home, I started researching on the internet to see if anyone else had experienced problems with their MB 450 GLS catching fire. Surprisingly, I found that recalls had been issued in April 2022 and March 2024 for a possible fire risk from a 48volt loose ground wire issue under the passenger seat. At that time supposedly there were no reported injuries or crashes related to this issue until now. If I am the first to witness this issue, then so be it because I saw the fire burning from inside under my passenger seat before it FULLY torched my vehicle I reported this issue first to Progressive Insurance and Mercedes-Benz Corporate. Progressive has provided my transportation according to policy for my first 30 days. As I approached the end of my rental period, I spoke with MB Corporate to see if there was anything that they could do as far as providing me transportation. I was told that there was nothing that they could do because they were not a dealership with cars to loan. The joint vehicle fire investigation was schelduled for 29 April 2025. On 25 April 2025, Progressive informed me that MB Corporate had moved the fire investigation date to 29 May 2025. NOW, what am I suppose to do? It has been almost two months that I have been without a vehicle. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6

NHTSA ODI 11661377

Aug 25, 2024Electrical systemSeatsFire

1. Unknown, smoke started coming from under the passenger side seat, car is a complete loss. 2. Smoke damaged my lungs, there was a large amount of exploding glass, and it could have led to a structure fire. 3. Not applicable 4. In process, but it was recalled for this issue 5. No

NHTSA ODI 11610699

Working with the data? Download all 36 complaints as CSV · fetched from NHTSA July 20, 2026

How to use these: a complaint is one owner’s report, filed voluntarily and published unverified. Patterns matter more than any single story. If several owners describe the same failure at similar mileage, put that system at the top of your pre-purchase inspection list. Back to the full 2021 Mercedes-benz GLS verdict →