MOT advisory explained
“Direction indicator slightly discoloured”
An indicator that flashes more white than amber. The colour is in a coating on the bulb glass, and the coating burns off over years of use. It is one of the few advisories where the fix costs pounds, and one of the few where the failure really is a one-word judgement.
Indicators must show amber. The tester saw one flashing with a noticeable white or pale tint, judged it still recognisably amber, and let it through. The next tester may not.
6.1% fail on an indicator at the next test, well above other lamp advisories. Once the amber coating has started to lift it goes quickly, and the line between slightly discoloured and not amber is one person’s opinion in daylight.
Indicator bulbs are a couple of pounds each. On most cars the rear ones are reached from inside the boot and the fronts through the headlamp unit or wheel arch liner.
The bulb, not the lens, on almost every car. Clear-lensed lights use a bulb with an amber coating, and that coating flakes. Only if the lens itself is amber and has gone pale is the lamp unit the problem. Check the bulb first, because the lamp unit costs a hundred times more.
A “direction indicator slightly discoloured” advisory means an indicator flashes paler than the amber the rules require, usually because the coloured coating on the bulb has faded, but it is still recognisably amber, so the car passes. The fix is a new amber bulb, costing £10–£40 for a pair. According to DVSA MOT data analysed by PriceMyRepair, 6.1% of 1.9 million such advisories followed to the next test failed on a direction indicator.
Where the colour comes from
Painted glass. Behind a clear lens the amber comes from a coating on the bulb itself. Heat from the filament bakes the coating a little every time the indicator runs, and after a few years it thins from the top of the glass down. The bulb keeps flashing, just paler. Silver-topped bulbs, sold to hide the amber when the lamp is off, lose their colour the same way.
Why testers write both. “both” is the most common note by a distance, with “both sides” and “both rear” behind it. Bulbs on the same corner of the car are the same age and have flashed the same number of times. When one has faded, its partner is close behind, which is why the advice is to change them as a pair.
The side repeater. One in nine of these advisories is for the small repeater in the front wing or door mirror. It uses a tiny bulb that runs hot in a sealed housing, and on some cars the plastic housing itself yellows. The rule and the fix are the same.
Will it fail next year?
Five wordings share this page. Together they have been recorded 5,413,424 times, and 1,901,107 can be followed to the same vehicle’s next MOT.
| What happened at the next test | Share |
|---|---|
| Failed on the same component | 6.1% |
| Same advisory recorded again | 19.6% |
According to DVSA MOT data analysed by PriceMyRepair: 1,901,107 advisories followed to the same vehicle’s next test. Rows can overlap.
For a lighting advisory this is high. A headlamp with a coating on the lens fails 5.0% of the time, a non-obligatory stop lamp 5.1%. The reason is that the fault is progressive and the test is subjective. A coating that has visibly started to go will look worse in a year, and a different tester on a brighter day will call it.
About one in five is advised again unchanged. Those are the owners who were not told that the fix is a two-pound bulb.
| Advisory wording | Fails on same part | Advised again | Followed |
|---|---|---|---|
| Tyre slightly damaged/cracking or perishing | 9.2% | 24.4% | 14,917,627 |
| Direction indicator slightly discoloured | 6.1% | 19.6% | 1,901,107 |
| Stop lamp(s) non-obligatory stop lamp not working | 5.1% | 26.3% | 526,670 |
| Headlamp has a product on the lens | 5.0% | 22.9% | 1,248,099 |
| Position lamp slightly affected by the operation of another lamp | 3.9% | 12.7% | 121,142 |
| Registration plate deteriorated | 3.7% | 40.1% | 4,283,862 |
| Brake pedal wearing smooth | 1.4% | 26.2% | 320,684 |
Bulbs fade with use, so the advisory tracks age until cars stop being driven much. It rises from 1.2 per 1,000 tests at 3–4 years to 18.8 in the late teens and then eases. The share that fail next time follows the same curve, peaking at 6.7% at 13–15 years.
| Age of car | Per 1,000 tests | Fails on same part | Followed |
|---|---|---|---|
| 3–4 years | 1.2 | 3.7% | 32,361 |
| 5–6 years | 3.4 | 4.5% | 96,502 |
| 7–9 years | 8.5 | 5.4% | 348,241 |
| 10–12 years | 16.3 | 6.3% | 539,825 |
| 13–15 years | 21.8 | 6.7% | 473,305 |
| 16–19 years | 23.0 | 6.6% | 309,947 |
| 20 years and over | 18.8 | 5.8% | 91,041 |
Most indicator bulbs are a bayonet fitting: push, quarter-turn, pull. The amber ones have offset pins so they cannot be fitted the wrong way round or swapped for a clear bulb. Buy a branded pair, because cheap coatings fade in months.
Rear lamps usually come out with two screws or a plastic wing nut inside the boot. Front ones vary: some through the bonnet, some by turning the wheel to full lock and unclipping the arch liner.
LED replacement bulbs in a lamp designed for a filament bulb are an MOT failure on most cars, however bright and amber they look. Stay with the type the car was built with.
Exact wording on your certificate
The advisory says slightly. The failure says the lamp is no longer amber at all, and it is the same person deciding.
| Line on the certificate | Result | Code |
|---|---|---|
| Direction indicator slightly discoloured | Advisory — pass | 4.4.3 (a) |
| Side repeater slightly discoloured | Advisory — pass | 4.4.3 (a) |
| All direction indicators slightly discoloured | Advisory — pass | 4.4.3 (a) |
| All direction indicators slightly affected by the operation of another lamp | Advisory — pass | 4.4.3 (b) |
| All direction indicators light intensity reduced | Advisory — pass | 4.4.3 (a) |
| Direction indicator emitted colour not amber | Major — fail | 4.4.3 (a) |
The two rear indicators account for more than half. They flash the same as the fronts but sit in a hotter, more enclosed lamp cluster with the brake and tail bulbs, and heat is what bakes the coating. The offside rear edges the nearside rear, which fits a lamp that faces the sun more often when parked.
| Position written by the tester | Share of all instances |
|---|---|
| Offside rear | 29% |
| Nearside rear | 28% |
| Offside front | 15% |
| Nearside front | 13% |
| Rear | 8% |
| Front | 3% |
From 5,413,424 recorded instances. Testers can add their own note after the standard wording. The most common on this advisory: “both” (177,487), “both sides” (98,664), “both rear” (52,029), “both front” (21,429), “nearside and offside” (18,117), “both rears” (13,322), “both side” (11,886), “side repeater” (8,032).
What it costs
| Job | Price fitted | Notes |
|---|---|---|
| Pair of amber indicator bulbs | £10–£40 | DIY. A garage adds a few minutes’ labour |
The price above is for branded bulbs from a motor factor or online. Any garage will fit them while the car is in for something else. If the lens itself has faded, a replacement lamp unit is priced by model and is a different order of cost. Repair prices are on the repair costs index.
Can I still drive with this advisory?
Change the bulbs when convenient, and before the next test. A lamp that has gone clearly white is illegal from that point, MOT or not, and the police can act on it.
Enter your reg to see every advisory on your car’s record, and whether this one has been written down on the same corner before.
Which cars get this advisory most?
The average vehicle gets this advisory on 9.4 of every 1,000 tests. The models below get it three to four times as often.
| Model | Per 1,000 tests | Vs all cars | Tests |
|---|---|---|---|
| Renault Scenic | 39 | 4.2× | 600,691 |
| Fiat Punto | 35 | 3.7× | 1,031,944 |
| Ford Fusion | 34 | 3.6× | 717,369 |
| Volvo V70 | 33 | 3.5× | 542,743 |
| Citroen C3 | 31 | 3.3× | 2,369,957 |
| Peugeot 207 | 28 | 3.0× | 2,075,563 |
| Nissan Micra | 26 | 2.8× | 2,941,349 |
| Citroen Berlingo | 25 | 2.7× | 2,070,097 |
| Vauxhall Agila | 23 | 2.5× | 435,853 |
| BMW 120 | 23 | 2.4× | 466,460 |
Model families are grouped by the first word of the DVSA model name, so “Transit” covers every Transit variant. Only models with at least 60,000 tests are ranked.
The Renault Scenic leads at 4.2 times the average, and the list is mostly French and Italian small cars of the same era: the Fiat Punto, Citroen C3, Peugeot 207 and Citroen Berlingo. Most of them left the factory with clear lenses and coated bulbs, and they are now old enough for the coating to have gone.
The Ford Fusion and Volvo V70 are there for age. Long-lived cars on their original bulbs.
What to do next
- Switch the hazards on and walk round. Compare each indicator with its partner. A faded one looks white next to a good one, even if it looked fine on its own.
- Check whether it is bulb or lens. Take the bulb out. If the glass is patchy or clear at the top, that is the fault. If the bulb is fine and the lens is pale, the lamp unit needs replacing.
- Change them in pairs. Both rears or both fronts. They have done the same work.
- Keep the spares. The old bulbs still work as emergency spares in the glovebox, for a bulb that fails outright.
Discoloured indicator advisory FAQ
What does direction indicator slightly discoloured mean on an MOT?
An indicator flashes paler than a proper amber, usually because the coloured coating on the bulb has faded. It is still recognisably amber, so it is an advisory and the car passes.
Is a discoloured indicator an MOT fail?
It becomes one when the lamp no longer shows amber. That is a judgement by the tester. According to DVSA MOT data analysed by PriceMyRepair, 6.1% of 1.9 million such advisories failed on an indicator at the next test.
How do I fix a discoloured indicator?
Replace the bulb with a new amber one, usually in pairs. If the bulb is fine and the lens has faded, the lamp unit needs replacing. Bulbs cost £10–£40 for a pair; lamp units vary by model. These are estimates and final quotes come from garages.
Can I fit LED indicator bulbs?
Not in a lamp designed for a filament bulb, on most cars. Aftermarket LED bulbs in those lamps are an MOT failure regardless of colour or brightness.
Why do indicator bulbs lose their colour?
Heat. The amber is a coating on the glass and the filament bakes it a little every flash. Rear indicators, in a hot enclosed cluster, fade first.
Which cars get this advisory most?
The Renault Scenic, Fiat Punto and Ford Fusion, at three to four times the average rate. Most of the top ten are small French and Italian cars now well into their teens.
How these figures were calculated. According to DVSA MOT data analysed by PriceMyRepair, from the DVSA anonymised MOT test results (Open Government Licence v3.0): 350,943,111 tests. This advisory was recorded 5,413,424 times; 1,901,107 of those were followed to the same vehicle’s next test between 180 and 730 days later. “Fails on the same part” means a failure at that next test under the same defect code and naming the same component, on either side of the vehicle. Testers do not always name a component the same way twice, so the figure is a floor. Method and how to cite.