3.0i Bi-Xenon Main Beam Broken

[[email protected]]

HI - Hope you can help with my first post (ever). I have a 2006 Z4 e85 3.0i with bi-xenon headlights that no longer go onto main beam properly. It seems a common problem in the forum - but I cannot see where to go next with my particular issue. Its driving me mad.

Issue: Main beam/flash works fine when cold and from start up. Turn on Engine and drive around for 3 mins and main beam stops and never comes back on. I suspect something its heating up causing the Main beam/flash to fail. When it cools again its OK. Both bulbs / shutters seem to work OK initially.

History: I have... taken to garage to diagnose who looked for over an hour and could not find the issue - but they suspected igniter or Ballast. Only error message on EDM was the stepper motors for the beam levelling which they got operational again as they said they got a bit stuck. So then I did my own tests and disconnected each side and tested dip/main until I could see that clearly drivers side was erratic and failed whereas passenger side appeared stable and never went wrong. Since then - I have replaced the drivers side ballast cpu, both bulbs, the bulb ignitor. Also - the entire headlamp unit and all components were replaced with new items by main dealer in 2019 costing me an insane £1315 - so I would expect the housing and ballast cable to be in excellent condition. There is no fogging or water ingress that I can see. Since then I have spent approx £200 on all the replacement parts and had the bumper/lights out taking it all apart and rebuilding. No error messages when checked with EDM now, no dash warnings lights on. Worked fine when on tested before car rebuild - but then after a few minutes failed again.

I went to check the fuses - but someone had historically removed the fuse card - and also - on the basis that all the functions work for the first few mins does not really indicate an issue with the fuses. I will check again but not expecting to see an issue here. Generally its work or not with fuses because they are circuit breakers.

At this stage I am looking at another huge bill that I just cannot afford. The rest of the car is OK and love my Z4. If I have to pay out to get it through an MOT - it means that this single headlight has more money spent than the value of the entire car.

I hope that I have missed a thread - or that there is a lighting / electronics expert on the forum that can identify what can be going wrong when I have already replaced all the parts. Do I need to replace all the parts on the side that's working too? It seems like a step too far. I cannot just go around the car endlessly replacing and hoping it will fix.

In principle its better to diagnose the issue properly rather than replace parts but in this case neither option has worked. I am not in the trade - just trying to fix my own car so I can get to work. I don't have many tools (or even a garage) - and even less idea as to what the heck is going on with my main beams but I have to get these working and I am starting to hate this situation. Please can some one help me with some suggestions - or is it main dealer & replace everything time?

[[email protected]]

It's been a few days and I have had some reads abut sadly no reply. Maybe I use too many words. I have been looking for replacement units - and I am starting to think that these headlights are quite difficult to find and a frustration for many Z4 owners. I cannot see any used ones that would work on ebay - so my plan is to take the part working ones apart and try to see if its a problem with the projector shutter inside. If I need to spend a fortune getting this fixed may as well have a bash first. If I fix it then I will let the forum know.

[E86]

Hi Scott,

Sounds like you have a reproducible fault so as you say it should be possible to diagnose without replacing all the parts again. It could even be something simple like a bad connection somewhere.

You can find information on the fuses here

Is your car pre or post facelift?
Is the main beam faulty on one side or both? Which side was replaced previously?

[dzefer]

Hi scott,

try to check the LCM, easy to remove, just a quick check. I have posted my problems here. So long story short, after I replaced the burnt IC, my lights started to work as expected.

[MKZ4000]

Have you tried going back to the main dealer under warranty ?

Most genuine Bmw parts come with a 2 year warranty

[MKZ4000]

Used xenon do come up from time to time but they are quite rare.

It seems strange that you had problems previously and are still getting issues after replacing them

[[email protected]]

Thank you for your comments - I now have this working. I took the whole unit out and took out the projector and gave it a thorough examination. I though that the shutter seemed a little stiff and rubbing against the frame so poked it and bent it slightly so that the shutter would open and close a bit more easily. On reconstruction I also made double sure that the shutter electrical connection was good. Now it is all working fine on both dip and main beam...and it didn't cost any more money.

I think that there is a tendency to assume this was electronic failure when I think it was actually a mechanical. If doing this again I would ask myself - are the bulbs working - if so then probably not an issue with bulbs or igniters. Second I would ask whether the shutters work at all - even briefly. This indicates that the LCM is possibly OK. I don't know all the LCM does but I suspect that mine was fine before I replaced.

Another thought is that if you disconnect one at a time you can identify which one has the working dip/main function. Sounds obvious but it was not clear which light failed as if one light cannot go to main beam it shuts the other one down. When I took it for diagnostics most time was spent looking at the wrong light.

The projector units on my car were Hella units. I was on the verge of replacing them before I managed to get them working. If I had wanted to replace the projected units (because the whole headlamps are a bit tricky to find) I was going to purchase from: https://retrofitlab.com/collections/bmw-z4-e85. I might still in the future - but if anyone is desperate or similar issue then this could help.

I didn't go back to the main dealer because I thought that the warranty was only a year. Also - its a bit of a last resort because I don't quite trust them as there have been issues with my car and I have not been 100% happy with the service. I probably need to use an alterative dealer when needed.

(The reason why the original unit was replaced was that a deer ran out and smashed the headlight in the rain and water got into the light and electronics - that is when the whole unit got replaced rather than some systemic issue.)

So now we are all good and have lots of light spares!

Thank you for your suggestions - hope this thread helps others in the future!

[MKZ4000]

Glad you got it fixed and well done for posting your solution. May help others in the future.