Mercedes-Benz B-Class: lighting & signalling MOT failures
Lighting & signalling was recorded as a failure area in 8.2% of Mercedes-Benz B-Class MOT tests — 35,427 tests out of 429,942. It shows up most on 2006 and 2010 cars.
Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair cost: £10–£150 (rough UK ballpark, not a quote).
Lighting & signalling failures by year
| Model year | Tests | Fail rate |
|---|---|---|
| 2005 | 3,546 | 14.0% |
| 2006 | 16,266 | 14.6% |
| 2007 | 20,165 | 13.6% |
| 2008 | 25,457 | 13.0% |
| 2009 | 30,409 | 12.9% |
| 2010 | 31,153 | 14.1% |
| 2011 | 23,983 | 14.1% |
| 2012 | 36,242 | 7.6% |
| 2013 | 43,034 | 7.3% |
| 2014 | 49,156 | 7.1% |
| 2015 | 32,705 | 5.4% |
| 2016 | 30,367 | 4.2% |
| 2017 | 31,974 | 3.6% |
| 2018 | 21,901 | 3.1% |
| 2019 | 18,488 | 1.7% |
| 2020 | 9,578 | 1.5% |
| 2021 | 3,947 | 1.6% |
| 2022 | 1,517 | 1.4% |
Methodology & source. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-27. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.