One DRL is half as bright as the other.

[Duvetday]

This nonsense with the failing nearside headlamps has got me wondering if the FType can ever be any sort of classic...whether it can be a car that will mature with age and increase in value ?

One option I had in mind with mine was to just keep hold of it for a long time, squirreled away in the garage and maybe enjoy a few thousand miles a year alongside another more ordinary mile munching car.

But seemingly with a high risk of a £3k bill every 3 or 4 years for a burnt out nearside headlights this would not seem viable ?

And wonder if the manufacturer cares if their cars become classics these days ?

Would an after market supplier ever make the investment to supply parts or would it not be worth their while ?

[WShudds]

A user (Tim Atkinson) mentioned a few pages ago about finding a solution for it. I don't think it's rocket science. I got some very clever engineers in the business who love fixing stuff. I could get them to have a look at a faulty unit in case anyone would like to donate theirs?

[Duvetday]

A user (Tim Atkinson) mentioned a few pages ago about finding a solution for it. I don't think it's rocket science. I got some very clever engineers in the business who love fixing stuff. I could get them to have a look at a faulty unit in case anyone would like to donate theirs?

Unfortunately Jaguar takes the old unit in and won't let you keep it when they replace...as condition of warranty or contribution agreement.

Funny that isn't it ?!

[lokiinlove]

Hi everyone!

My MY18 also got this issue. I bought it 2021 with 17k kms, in 2023 few times i noticed led drl randomly flickering sometimes. I could never replicate this issue at will, so dealer couldnt help. This year, at around 55k kms i noticed left DRL being dimmer than right one. This also applies to turn signal. Aside from that, if you stay with low beams on against wall pretty close, you can notice that low beam also is slightly dimmer (more obvious that its warmer CCT, which to me indicated that its underpowered, as white InGaN leds tend to decrease CCT when underpowered, and increase when driven with higher current). Same applies for high beam. So the whole headlight is dimmer. This raised a question, how can quite different leds with quite different working conditions (drl on all the time, low beams more rare, high beams i almost never use, turn signal blinks and total operating hours are nothing) degrade with same intensity. Seemed like nonsense. So i swapped left and right one and problem persisted in headlight, which indicated the headlight issue. Then i sent car to a headlight guy i found locally, asked him to open headlights and check pcbs with leds. Visually leds are completely ok (i work in led lighting industry for 13 years and seen some shit, so can visually check even for light degradation). Then i asked him to swap control units located in headlight, and to my surprise the problem stayed at same headlight, so probably not control module issue. Then we measured leds resistance (for leds resistance drops as degradation level increases), and there was no significant difference between left and right leds. Later i’ll post pics with resistance for all hb and lb chips. To verify the conclusion its not the chips, the pcbs will be sent to the lab where i work, where my engineer will drive them from external lab grade psu in order to eliminate any control module failure influence on brightness, and then test them in reflecting sphere with lad grade photospectroradiometer to find out if there is any difference it total lx output, lm output, cct, cri and other spectral and photo stuff.


Initially i suspected control module or wiring to the control module, but all that seems totally fine. Now only whats left is wiring from headlight internal control module to pcb and a bunch of capacitors and resistors on PCB. There is absolutely nothing else left.

The guy can replace leds if needed (though its not easy as hb and lb leds have special angle when layed on heatsink), rr velar headlights use same leds, and they are not hard to find used for cheap. We found one for like 300 bucks in working condition, just the housing is broken, which i dont need anyway. But i still think its not the leds. Even if leds, it will not fix the reason, and the problem will reoccur later, as it happens with new headlights here in this thread.

Another idea i have is to fit long thermocouples inside left and right headlight and in the engine bay near the headlights, and drive the hell out of car, monitoring live whether there is any temp difference inside headlight or on left/right of engine bay. No hopes here, just wanna do this and confirm that its not the case.

I’ll keep this thread updated as i progress on this. If anyone has any electrical engineering insights, ideas, or you know something about this issue - pls share, i’m willing to collaborate on this and find the reason. No problem in buying headlight, but that does not fix anything and also boring. Tearing down stuff and finding reasons is fun

[lokiinlove]

Btw, if you are having this issue with drl, try that staying against wall thing and feedback if you notice the difference. Its even less obvious than drl, but spottable. Wonder if thats only my case or others also have it. I feel should be same for everyone.

[lokiinlove]

Another thing which confirms its not the leds - CCT decrease. When led degrade, the luminophore (yellow stuff which makes blue light of InGaN led white) burns out, allowing more of blue light to pass through, so the CCT increases making emitted light colder, more blueish. Which is opposite of whats going on irl with my headlight

[scm]

Another thing which confirms its not the leds - CCT decrease. When led degrade, the luminophore (yellow stuff which makes blue light of InGaN led white) burns out, allowing more of blue light to pass through, so the CCT increases making emitted light colder, more blueish. Which is opposite of whats going on irl with my headlight

Have you read the other posts in this thread - it's made quite clear what the problem is.

[WShudds]

Hi everyone!

My MY18 also got this issue. I bought it 2021 with 17k kms, in 2023 few times i noticed led drl randomly flickering sometimes. I could never replicate this issue at will, so dealer couldnt help. This year, at around 55k kms i noticed left DRL being dimmer than right one. This also applies to turn signal. Aside from that, if you stay with low beams on against wall pretty close, you can notice that low beam also is slightly dimmer (more obvious that its warmer CCT, which to me indicated that its underpowered, as white InGaN leds tend to decrease CCT when underpowered, and increase when driven with higher current). Same applies for high beam. So the whole headlight is dimmer. This raised a question, how can quite different leds with quite different working conditions (drl on all the time, low beams more rare, high beams i almost never use, turn signal blinks and total operating hours are nothing) degrade with same intensity. Seemed like nonsense. So i swapped left and right one and problem persisted in headlight, which indicated the headlight issue. Then i sent car to a headlight guy i found locally, asked him to open headlights and check pcbs with leds. Visually leds are completely ok (i work in led lighting industry for 13 years and seen some shit, so can visually check even for light degradation). Then i asked him to swap control units located in headlight, and to my surprise the problem stayed at same headlight, so probably not control module issue. Then we measured leds resistance (for leds resistance drops as degradation level increases), and there was no significant difference between left and right leds. Later i’ll post pics with resistance for all hb and lb chips. To verify the conclusion its not the chips, the pcbs will be sent to the lab where i work, where my engineer will drive them from external lab grade psu in order to eliminate any control module failure influence on brightness, and then test them in reflecting sphere with lad grade photospectroradiometer to find out if there is any difference it total lx output, lm output, cct, cri and other spectral and photo stuff.


Initially i suspected control module or wiring to the control module, but all that seems totally fine. Now only whats left is wiring from headlight internal control module to pcb and a bunch of capacitors and resistors on PCB. There is absolutely nothing else left.

The guy can replace leds if needed (though its not easy as hb and lb leds have special angle when layed on heatsink), rr velar headlights use same leds, and they are not hard to find used for cheap. We found one for like 300 bucks in working condition, just the housing is broken, which i dont need anyway. But i still think its not the leds. Even if leds, it will not fix the reason, and the problem will reoccur later, as it happens with new headlights here in this thread.

Another idea i have is to fit long thermocouples inside left and right headlight and in the engine bay near the headlights, and drive the hell out of car, monitoring live whether there is any temp difference inside headlight or on left/right of engine bay. No hopes here, just wanna do this and confirm that its not the case.

I’ll keep this thread updated as i progress on this. If anyone has any electrical engineering insights, ideas, or you know something about this issue - pls share, i’m willing to collaborate on this and find the reason. No problem in buying headlight, but that does not fix anything and also boring. Tearing down stuff and finding reasons is fun

Fantastic job, thank you. I too work in Electronics and was thinking about all these different approaches which you've gone through already.

Even if you haven't found the root cause of the issue, it's great that your investigation has ruled out a lot of things.

[Tim Atkinson]

A user (Tim Atkinson) mentioned a few pages ago about finding a solution for it. I don't think it's rocket science. I got some very clever engineers in the business who love fixing stuff. I could get them to have a look at a faulty unit in case anyone would like to donate theirs?

Thanks for the mention...

I'll update you on the situation:

I'm continuing to work on this with a highly experienced headlamp specialist in the UK, and we met last week in person again. We understand the nature and cause of the failure, which is overheating of the light rod near the LED source, causing distortion and discolouration. This is not in doubt.

We are in touch with a manufacturer in China (I know...) who has patterned the parts in order to make production tooling. They investigated the existing light rods and found that they are already made of the highest-quality, most heat-resistant material, so improving the heat-resistance of the rods we manufacture is not a complete answer; replacing failed ones with the our new rods in itself will provide a solution at vastly lower cost than the JLR answer, but without a guarantee of enduring reliability, unless we tackle the heat problem.

So, I had a meeting yesterday with an electronics specialist who helps us with business things from time to time and who is very familiar with the issues involved. First, a quick win: we have identified that conductive paste between the LED source PCB and its heatsink, as applied on the one we inspected, is insufficient in quantity of not of the highest quality, so the first option is, when replacing the rods, to dissemble, clean, and reassemble these components with better, and the right amount of, paste. That should improve the conductive transfer of heat from the LED PCB to the heatsink. I was glad to find this because it answers my most troubling question, which is, 'If designed correctly and diligently, how are these failures occurring?' in the simplest way.

However, in case that is not sufficient, we are also looking at how the LED pulse width is modulated. LED brightness, and therefore operating temperature, is a product of the design of the LED and its pulse width, the LEDs are not continuously illuminated but flash very fast, in a way invisible to the human eye but which you see sometimes when LEDs are captured with a movie camera. If we can reduce the time the LED is illuminated (the ON-time), we will only lose a little brightness, but significantly reduce the heating. We have a question in with a JLR expert about whether the ON-time is coded into software, and we shall shortly strip another headlamp unit at the electronics lab, to see whether it's determined by hardware. Either way, if we can find a way to decrease the ON-time, that will lower the temperature of the LED cluster, and mean we have an enduring solution.

We discussed, and dismissed, other options such as increasing the size of the heatsink (there isn't enough clearance for it), manufacturing more efficient heatsinks out of copper (too expensive) and providing additional ventilation, by fitting a fan directed at the heatsink (too complicated and costly).

An outstanding question remains as to how we fund this work, and given the numbers involved, we may perhaps put it out to crowd-funding.

Either way, this is one place where you will be kept up-to-date.

[WShudds]

Brilliant post, thank you for the update and all the time you're putting into this. I used to sell and provide support to OEMs using heat conductive pastes and pads and the process followed by many is abhorrent due to lack of education. I won't bother people here with details but it makes sense that a low quality paste applied incorrectly (too much or too little) will bleed out creating gaps that will cause the PCB to overheat. My question is whether the excessive heat can cause permanent damage to some devices otherwise the LEDs "should" work when cold and then become dimmed after a few minutes.

Regarding the ON-time, I suggested several posts ago that it should be possible to code it through the ECU giving the ability to reduce intensity to a more manageable and less taxing level but within MOT specifications.

I like and support the crowd funding option.