Common problems

Mercedes-Benz A-Class electrical and lighting problems

How often MOT testers find lights and electrics faults on the Mercedes-Benz A-Class at each age, against all cars of the same age, and which items come up most. From 1,360,594 DVSA MOT tests taken 2022 to 2025.

MOT data updated 28 September 2026

At 6 years, the most tested age

Lights and electrics fails per 100 MOTs (n=173,010)2.6

All cars at 6 years (n=10,382,720)4.7

Lights and electrics advisories and minor defects per 100 MOTs (n=173,010)0.5

All cars, same age (n=10,382,720)1.9

What stands out

At 6 years, 2.6 of every 100 MOTs of the Mercedes-Benz A-Class found a lights and electrics fail (n=173,010), against 4.7 for all cars of that age (n=10,382,720).
It is above the all-car rate at 4 of the 21 ages with at least 1,000 tests.
The gap is widest at 11 years: 9.4 per 100 MOTs against 13.3 for all cars.
The lights and electrics fail item recorded most often at 6 years: headlamp aim: too low, on 0.7 per 100 MOTs.

Lights and electrics fails by age

Solid line: this model. Dashed line: all cars at the same age.

Mercedes-Benz A-Class: lights and electrics fails and advisories per 100 MOTs, by age, against all cars. Ages with fewer than 1,000 tests are not shown.
Age	Tests (n)	Fails	All cars	Advisories	All cars
3 years	141,475	1.5	2.9	0.2	0.7
4 years	161,782	1.5	3.1	0.3	1.0
5 years	171,041	2.0	3.7	0.4	1.3
6 years	173,010	2.6	4.7	0.5	1.9
7 years	148,489	3.8	5.8	0.8	2.5
8 years	130,797	5.3	7.3	1.1	3.4
9 years	105,453	6.5	9.2	1.6	4.5
10 years	72,287	8.2	11.2	2.1	5.9
11 years	50,730	9.4	13.3	2.7	7.5
12 years	33,511	11.9	15.4	3.6	9.3
13 years	25,200	15.1	17.0	5.7	10.8
14 years	27,065	15.6	18.3	7.3	12.2
15 years	27,947	17.0	19.5	8.6	13.7
16 years	26,573	17.4	20.4	9.3	15.3
17 years	22,127	18.1	21.0	11.0	16.9
18 years	15,715	20.5	21.4	13.0	17.8
19 years	10,656	20.3	21.5	14.9	17.9
20 years	7,083	22.2	21.2	18.5	17.4
21 years	4,505	22.2	20.6	20.7	16.7
22 years	3,184	23.0	19.7	21.0	15.5
23 years	1,964	21.4	18.6	19.9	14.2

Lights and electrics fail items at 6 years

Lights and electrics fail items on the Mercedes-Benz A-Class at 6 years (n=173,010), per 100 MOTs, with all cars at the same age (n=10,382,720).
Item	Per 100 MOTs	All cars	Typical repair (estimate)
Headlamp aim: too low	0.7	0.8	£16 to £39 per car (rough guide)
Headlight aimed too high	0.6	0.6	£16 to £39 per car (rough guide)
Dipped headlight not working	0.4	0.7	£18 to £86 per lamp
Side repeaters: not working	0.3	0.2	£10 to £47 per lamp

Repair estimates are a guide for an independent garage: labour at the national median local garage rate (median £78 an hour from 65 garages, ONS price quotes) times estimated labour hours, plus a parts band. Labour hours and most parts bands are estimates, not quotes, and prices vary by model, engine and region. A warning light fault shows the cost of the diagnosis only.

What to check on a viewing

On the Mercedes-Benz A-Class, the lights and electrics items testers fail most are headlamp aim: too low; headlight aimed too high; dipped headlight not working.

With someone outside, try every light: dipped and main beam, indicators, brake lights, fog lights and number plate lamps.
Check that the warning lights come on with the ignition and go out once the engine runs.
Look for misted, cracked or yellowed headlamp lenses.

Ask for the car's MOT history: a lights and electrics advisory that repeats from year to year has not been fixed. GOV.UK MOT history.

Questions

What are the common electrical and lighting problems on the Mercedes-Benz A-Class?

At 6 years (173,010 MOTs), the lights and electrics fail items testers record most often are headlamp aim: too low (0.7 per 100 MOTs), headlight aimed too high (0.6 per 100 MOTs), dipped headlight not working (0.4 per 100 MOTs).

Does the Mercedes-Benz A-Class have more electrical and lighting problems than other cars?

At 6 years it has 2.6 lights and electrics fails per 100 MOTs against 4.7 for all cars of the same age (2.1 fewer). It is above the all-car rate at 4 of the 21 ages with enough tests.

What does a lights and electrics repair cost on the Mercedes-Benz A-Class?

For headlamp aim: too low, an independent garage estimate is £16 to £39 per car (rough guide). This is a guide built from the national median garage labour rate and estimated labour hours, not a quote.

Electrical and lighting problems on other Mercedes-Benz models

Read this with care. A fail rate is not a measure of build quality. How far cars are driven, how they are used and how well owners maintain them all change it, and wear items such as tyres and brake pads are common fails. Compare a model only with cars of the same age. Methodology and limits.

The all cars figures cover all class 4 vehicles (cars and light vans) tested at the same age.

Looking at a Mercedes-Benz A-Class?

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Repair estimates: ONS consumer price quotes for local garage labour (09/2025 to 08/2026), the MOT inspection manual for defect wording, and estimated labour hours and parts bands. Not affiliated with or endorsed by ONS.

Source

Contains public sector information licensed under the Open Government Licence v3.0. Source: DVSA anonymised MOT test data, class 4 normal MOT tests, 2022 to 2025. MOT data updated 28 September 2026.

Not affiliated with or endorsed by DVSA. How we calculate these figures · Data sources