dimetrius
Member Since: 20 Apr 2021
Location: St. Petersburg
Posts: 24
 
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| Headlight problems: dim, discoloured, etc., including L405 | |
Greetings all!
After searching online for solutions to my problems with headlights, I've come across a vast amount of information that I've summarised and would like to share with those that may find it useful. There are other threads on the matter, but I felt a single summary would be easy to find and apply. Plus, it includes some information I found in other sources.
The issues and solutions described concern HID (Xenon) lights, not just on L322, but on all cars in general. If you are considering getting after market LED, you may find some information useful as well.
Dim headlights
10% of the causes:
- Road rash on front cover lens
- Bulbs
- HID ballast / igniter
Road rash on the front cover lens
Your mileage may vary. Some people get this, some don't. If you have, it's pretty easy to spot as the lens will not be clear. Easy enough to polish, make sure you use the right tools and paste as these lenses are quite soft. Some say they have an UV coating that will be removed when polishing, so it's probably a good idea to get a transparent film (e.g. 3M) and protect them from UV damage and road rash in the future.
Bulbs
Bulbs going out (burning out) usually results in rapid deterioration of the colour and intensity. Usually happens on one side.
HID Balast / Igniter
HID Igniters going out will result in dim, flickering lights, that will rapidly deteriorate and result in the light not working at all. Usually happens on one side.
90% of the causes:
- Lens projectors (reflectors)
Lens Projectors (reflectors)
This is the main cause for the dim sometimes discoloured lights.
Lens projectors have a rather thin (few microns) layer of aluminium on them, which is applied in a vacuum chamber to dozens of projectors at a time. High temperature and intensity of the Xenon HID lights burn these out with time (especially on L322 with Scandinavian DRL that turn xenons on pretty much all the time).
Some random pics from the internet to illustrate the issue:
Let's look at possible ways to fix this:
- Replace the headlights
- Replace the lens
- Restore the lens
- Go LED
Replace the headlights
This is the route the manufacturer clearly wants you to take. And you can't blame it on the greediness. Because making any modifications to the inner workings of these rather sophisticated lighting systems will most likely require specific paperwork to be filed for modifications, might make it harder to pass MOT type tests, and may make the vehicle hazardous and dazzling to other people on the road.
Replacing the headlights is rather expensive. L322 OEM headlights cost well over £1,000 each. There are cheap knock-offs with Xenon and LED, which I would avoid in favour of the next option.
Thankfully, you can find the original manufacturer and buy equipment from their dealers in most cases. In the case of L322 (and L494) it's Magneti Marelli. If you buy the headlights from them, they'll be just around £500 each, yet it's not just OEM quality, it's actual OEM.
This is the route I might end up taking with my headlights as I have also some light pattern etching damage to the headlight cover on the driver's side.
Replace the lens
A much cheaper but more labour intensive alternative is to replace the lens assembly (or just the reflector/projector part). There are many nuances to this.
Probably a good idea to avoid repair kits since the quality may differ significantly from one kit to the other.
Another possibly good idea is to avoid knock-offs from China and Korea (there are a lot "upgrade" versions of the most popular lens assemblies) - the quality control on these will vary greatly and you may end up wasting time and money. Another important difference is that most non-OEM lenses are polished smooth and clear, whilst the OEM lenses have a shagreen-like rougher cloudier surface - this is to make the light-shadow border wider and smoother, which is apparently easier on your eyes and causes less fatigue at night.
Getting OEM lens assemblies is probably the next best alternative to replacing the headlights completely. In the case of L322 these are Bosch AL-3.
Problem is, unlike the headlight which you can buy, these units are not sold anywhere on their own (except for Chinese and Korean knock-offs). The Bosch, Valeo, Hella, etc. factories only sell them to headlight manufacturers in batches.
Thankfully however, headlights are a frequent insurance item, meaning there are plenty of broken headlights in local scrapyards around you. Usually shops specialising on such items buy them from scrapyards and take them apart. These can be from cars as recent as 2020 BMW X6, X4, X5, and a plethora of other models and manufacturers. Unlike on L322, these have dedicated DRL that work without the Xenons and the mileage of a particular vehicle when the accident happens can be ridiculously low, providing you with a unit that's almost as new.
These can cost anywhere between £30-£80 for a pair depending on the condition and will likely provide you with factory new light pattern and intensity for the next 3-7 years.
Replacing them is somewhat labour intensive, as you have to take out your headlights, take them apart by removing the front lens covers and re-attaching them (well-known parts suppliers sell chemical liquids to penetrate through the solid adhesive, as well as the solid butyl adhesive tapes). This potentially involves using your oven  . There are guides online on how to do that.
As long as you replace the lens assembly with another OEM lens assembly, you shouldn't have to do any calibration and shouldn't have any problems with MOT and the like.
Restore the lens
There are shops that will offer lens restoration, some will even offer "polishing". We'll rule out both quickly:
Polishing - there is nothing to polish, it's a few micron thick aluminium layer parts of which have evaporated.
Restoring - some shops will use chrome (aluminium reflects 40% more light); some will claim to use aluminium, but given the technology required for this (gases, electricity, chamber sizes, etc.) it's economically unviable to use the factory process involving aluminium vapours on fewer than 30-40 reflectors at a time.
I would avoid restoration altogether.
Go LED
I'm including this here only because many shops will try to sell you LED. IMHO, LED only makes sense if it's intelligent LED a.k.a. matrix. We have it on MB and it's absolutely stunning, the ability to have full-beam turned on pretty much all the time as well as road side and road sign intelligent lighting make night driving quite relaxing.
Halogen to LED. Some might say that upgrading halogen to LED may be worth considering. It is worth considering in my opinion. But if you live in an area with not a lot of sun, the yellowish halogen light may actually be more comfortable. With current advances in halogen lamps (just look at what Osram is offering), you might be better off just upgrading the lamps. Or look at factory adaptive bi-xenon headlights with auto high beams.
Xenon to LED. Xenon gives a really good lighting temperature and brightness. Again, there are modern HID lamps that can light 400m+ ahead, almost as far as lasers. Your car is already equipped with HID, LED will not make a whole lot of difference. Next generation xenon bulbs will. Additionally, you will have to do additional wiring for LED, since they work at different voltage than HID.
Generally, with LED, you have to consider the fact that these generate a lot of heat. And dissipating that heat effectively usually requires accommodations under the bonnet. Until intelligent LED kits are available, I personally don't think it's worth the effort - after market LED is not the same as factory designed and engineered LED.
Front lens light etching / damage
This is known to happen sometimes. I found several threads about this happening to W212 e-class. Sometimes it's chemical vapour that can be wiped away with isopropyl. Often however, it's actual light pattern etching on the plastic. No one quite knows why this happens (except for factory engineers I suppose); it may be related to reflectors burning out and changing the light focus/pattern, or perhaps a bad batch of reflectors/bulbs/front lenses. When isopropyl doesn't work, it looks like there are only two solutions: buy a non-OEM plastic cover lens to replace the original, or buy the headlight assembly (more on that above).
DRL
L322 officially has a Canadian type DRL with high beams on low intensity, as well as a Scandinavian type DRL with LED strips as well as Xenon always on, as far as I'm aware. There are ways to enable just the LED strips with IIDTool as DRL. I considered it since that would potentially increase the lifespan of the HID lens assembly, but I think there is a reason LED strip only DRL is not officially available for L322 - these are not as bright as LED strips on L405 or D4.
All of the above is my personal opinion and is not a recommendation. I hope you find this post useful! 2009 Range Rover Westminster 3.6 TDV8 Alaska White/Jet
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3rd May 2021 9:04pm
