Common problems

MG TF electrical and lighting problems

How often MOT testers find lights and electrics faults on the MG TF at each age, against all cars of the same age, and which items come up most. From 36,093 DVSA MOT tests taken 2022 to 2025.

MOT data updated 28 September 2026

At 20 years, the most tested age

Lights and electrics fails per 100 MOTs (n=8,863)10.4

All cars at 20 years (n=1,845,952)21.2

Lights and electrics advisories and minor defects per 100 MOTs (n=8,863)7.1

All cars, same age (n=1,845,952)17.4

What stands out

At 20 years, 10.4 of every 100 MOTs of the MG TF found a lights and electrics fail (n=8,863), against 21.2 for all cars of that age (n=1,845,952).
It is level with or below the all-car rate at every age with at least 1,000 tests.
The gap is widest at 18 years: 9.0 per 100 MOTs against 21.4 for all cars.
The lights and electrics fail item recorded most often at 20 years: horn: not working, on 2.9 per 100 MOTs.
The most common lights and electrics advisory or minor defect: individual direction indicators: slightly discoloured, on 1.4 per 100 MOTs.

Lights and electrics fails by age

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

MG TF: 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
17 years	1,897	9.1	21.0	5.6	16.9
18 years	4,733	9.0	21.4	5.9	17.8
19 years	7,588	10.9	21.5	6.6	17.9
20 years	8,863	10.4	21.2	7.1	17.4
21 years	7,018	10.0	20.6	7.7	16.7
22 years	4,337	11.4	19.7	7.8	15.5
23 years	1,657	9.5	18.6	6.7	14.2

Lights and electrics fail items at 20 years

Lights and electrics fail items on the MG TF at 20 years (n=8,863), per 100 MOTs, with all cars at the same age (n=1,845,952).
Item	Per 100 MOTs	All cars	Typical repair (estimate)
Horn: not working	2.9	0.7	£33 to £113 per car (rough guide)
Side/position light not working	1.3	5.2	£10 to £47 per lamp
Brake light not working	1.1	3.9	£10 to £47 per lamp
Headlamp aim: projected beam image is obviously incorrect	0.9	4.0	£16 to £39 per car (rough guide)

Lights and electrics advisories and minor defects at 20 years

Advisories and minor defects are recorded, but the car still passes. Across all cars, a part with an advisory or minor defect failed at the next MOT 5.5 times in 100 (n=88,666,940 pairs of consecutive MOTs), against 0.3 times in 100 when the same part had none (n=12,936,860,350).

Lights and electrics advisories and minor defects on the MG TF at 20 years (n=8,863), per 100 MOTs, with all cars at the same age (n=1,845,952).
Item	Per 100 MOTs	All cars	If it needs replacing (estimate)
Individual direction indicators: slightly discoloured	1.4	1.8	£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 MG TF, the lights and electrics items testers fail most are horn: not working; side/position light not working; brake light 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 MG TF?

At 20 years (8,863 MOTs), the lights and electrics fail items testers record most often are horn: not working (2.9 per 100 MOTs), side/position light not working (1.3 per 100 MOTs), brake light not working (1.1 per 100 MOTs). The most common lights and electrics advisories or minor defects are individual direction indicators: slightly discoloured (1.4).

Does the MG TF have more electrical and lighting problems than other cars?

At 20 years it has 10.4 lights and electrics fails per 100 MOTs against 21.2 for all cars of the same age (10.8 fewer). It is level with or below the all-car rate at every age with enough tests.

What does a lights and electrics repair cost on the MG TF?

For horn: not working, an independent garage estimate is £33 to £113 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 MG 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 MG TF?

These figures describe the model, not the car in front of you. Found one you might buy? See what the VetTheCar Buying Report covers, or use the tools that work without a registration.

See a sample report Car tools · MOT fail rates by model · Compare models by MOT record

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