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MOT rule change LED bulbs in headlights

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I've just seen this on another forum. It was posted by an MOT tester...


The upgrading of existing halogen headlamps with HID bulbs has been a MOT fail for a few years now. However upgrading with LED bulbs was OK. Not anymore! From 11/01/2021 the MOT rules have been updated to make the fitment of LED bulbs ( in existing halogen units) a fail.

I attach the new rule for clarity.

4. Lamps, reflectors and electrical equipment

4.1.4 Headlamps - Compliance with requirements - Changed sentence from 'Existing halogen headlamp units should not be converted to be used with HID bulbs. If such a conversion has been done, you must fail the headlamp.' to 'Existing halogen headlamp units should not be converted to be used with high intensity discharge (HID) or light emitting diode (LED) bulbs. If such a conversion has been done, you must fail the headlamp.'
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Interesting rule change! Of course, fitting LED bulbs does not necessarily equate to dazzling headlights, as a well engineered LED device would replicate, or better, the bulb it is intended to replace. I have Philips LED bulbs in my kit which, although bright, easily met the criteria of no light in the dazzle zone in previous MOTs. Actually, the tester noted that the horizontal cut-off was way better than that of H4 filament bulbs in similar headlights.

I believe the burning question is: what dictates an "existing halogen headlamp unit"?

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I may be showing my ignorance, but I thought the test checked the pattern and intensity of the light so why does anyone care whether the actual emitting source of light is a conventional filament bulb, a HID gas bulb or an LED? So, like said above, if the output of light conforms to the requirements in terms of spread, not blinding anyone, etc then I'm curious as to why it matters (assuming e-marked, etc, that's all fine)... presumably the MOT test doesn't check some critical aspect (genuinely curious)?

edit: did a google

Makes an interesting point that I've always felt that even new cars with LED lights seem to be harder on my eyes (as an oncoming driver) than the old ones :) but that's probably just me getting old!

Edited by brumster
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It is probably the same with all car improvements -- until we are all using the same technology ( LED lights, ABS brakes, ) those with a "lessor" standard will be at a disadvantage.  We must wait & see what "issues" self driving cars bring or all electric vehicles dead on the side of the road waiting for the AA man with a can of "juice". 

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