Xenon Main beam

[Jonlane]

Hi All,
I hope someone can help me on this as my cars just failed its MOT on inoperative main beam on both headlights.
My car is an 06 model with factory fit Xenons (checked build sheet and factory fit) .
The headlights work with following scenarios
Sidelights = ok (Inner halo type)
Dipped beam = ok (Xenon on)
Flash to pass =ok ( think this is a separate bulb)
Main beam = NO (Dash blue light indicates they are on but plainly not at MOT station)
Ive done a fair bit of research on here and other forums and there is a confusing array of answers !
Looked at the obvious first, fuses okay so not a simple fix.
Any help would be most appreciated.
I understand that there are no main and dipped bulb as such and its the shutter that alters the light pattern, this seems to be the nub of the problem in that the shutters aren’t working. Would i be really unlucky in that both headlight modules are duff or is this not uncommon?
Could it be the light Ecu/contol module that’s at fault ?
Has anyone got a wiring diagram of the lighting circuit or know the pin outs on the headlamp unit ?
Could it be bad earths ?
If i can get the pin outs and put a supply on the shutter i assume you should be able to hear it operating .
Sorry for all the questions but I’m a bit stuck with no car, I’m still working (key worker) so i need the car legal !

 

[biojo]

you can tell if the shutters are working they make a noise. like a clicking sound.

Odd both arent working, have you checked for your self its not working?

 

[E86]

As biojo suggested, confirm for yourself that the main beams aren't working. In the dark, park facing a wall and check the patterns.

As far as I know, the flash uses the same bulb. Some BMWs use the inner lights for the mains so it's possible that's what the MOT tester was expecting.

Your MOT should have been extended by 6 months assuming it was due after 30 March 2020.

 

[Jonlane]

Hi thanks for the suggestions however after some investigation this is what I’ve come up with:
The high beams definitely don’t work, no change in light pattern and ultimately no audible click from the shutters either side when either flash to pass or on high beam.
After some investigation I’ve figured out how they work on my model year, (probably well documented on here) only one bulb for high and low which is the Xenon and also this is used for flash to pass.
After some digging around and looking at the wiring diagrams pin eight on the headlamp multiplug feeds the shutter and the rest are for the Xenon bulb/indicators etc. What i found a bit odd was that after testing the voltage at the pin it showed a few micro volts in the off position and around three volts when energised. I’m sure I’d read it was supposed to pull around 12 Volts, I disconnected the plug sent pin 7 i think down to dec and put 12 Volts on pin 8, i thought i heard a click and was pleased that the shutter appeared to work. Unfortunately I couldn’t repeat this test and didn’t get a click agin when testing a few times . After some head scratching i tested pin 8 Voltage again with the lamp plugged up (used a pin into wire tester) and it showe a continuous 11 Volts regardless of position of high beam switch !!!!!!
So after much messing around I’ve not really got anywhere apart from confusing myself !
I’m not sure if the solenoids for both lamp shutters are knackered or the signal they are getting isn’t correct, i think i would be really unlucky for both lamps to have the same fault but i suppose its not impossible.
Does anyone know ultimately where the shutters get the signal to operate from, is it the LCZ i.e the light switch or another light control module ?
I still suspect a wiring or signal fault but maybe both lamps are duff,

 

[biojo]

does the dash show full beam going on and off?

this might be a silly question but do the lights auto level?

 

[Jonlane]

does the dash show full beam going on and off?

this might be a silly question but do the lights auto level?

Yes the blue high beam comes on and the lights level when turned on. Code reader on live data reports that the high beam is selected, so i doubt if its an module issue. Its either no signal is getting to the xenon shutter or the shutters are both faulty, finding out where the fault lies without a spare headlamp is going to be tricky, test lamp and multi meter time
I do now have access to BMW WDS wiring diagrams and the workshop software so if anyone else is looking for wiring info shout up.

 

[biojo]

I wouldnt think both headlights would fail tbh

Have you checked all the fuses?
https://z4-forum.com/forum/viewtopic.php?t=38888

Sure u can connect 12v to the shutter so where see / hear it move

this might help you know where cables go http://www.unofficialbmw.com/images/6186EN.pdf

 

[Jonlane]

I wouldnt think both headlights would fail tbh

Have you checked all the fuses?
https://z4-forum.com/forum/viewtopic.php?t=38888
Thanks for the info, appreciated.
Yes all the fuses are good and I’ve seen that wiring diagram from another forum, some good info. I would be surprised if both headlights were faulty as well though it’s not impossible. Tried putting 12V across the shutters but it was inconclusive, might have another go tomorrow. I’m still convinced it’s wiring, either a bad earth or maybe a short, however as the wires to pin 8 are not a single circuit controlling both lamps it would be unlucky for both wires to be broken. I’m going to trace them out from the LC to the headlamps tomorrow to check for continuity.

Sure u can connect 12v to the shutter so where see / hear it move

this might help you know where cables go http://www.unofficialbmw.com/images/6186EN.pdf

 

[Jonlane]

does the dash show full beam going on and off?

this might be a silly question but do the lights auto level?

Yes the blue high beam comes on and the lights level when turned on. Code reader on live data reports that the high beam is selected, so i doubt if its an module issue. Its either no signal is getting to the xenon shutter or the shutters are both faulty, finding out where the fault lies without a spare headlamp is going to be tricky, test lamp and multi meter time
I do now have access to BMW WDS wiring diagrams and the workshop software so if anyone else is looking for wiring info shout up.

I’m a bit of a lurker more than a poster but i thought I’d give an update to the headlight fault, pass on my experience, pain and ultimately a successful fix !
As I said in the original post both lamps failed to work on main beam and after exhausting all the possibilities of easy fixes such as fuses, relays and wiring it was time to check out the electronics !
To cut a long story short when you flicked on main beam the LCM (headlight switch) turned on the sidelights, the wiring was correct (all the wires were pin tested, earths checked cleaned and the shutters operated when a voltage was put across them ) I removed the LCM and had a good look at it and found a surface mount component had burnt out and was shorting to deck .This short naturally drained my battery eventually because there was a permanent draw because of the short.
Finding the correct LCM for a facelift with Xenons second hand was a royal pain, they are extremely scarce !
I eventually bought one from BMW, with a bit of a discount it came to £232, not cheap but far cheaper than new headlights.
Took ten minutes to code and hey presto I now have functions headlamps, so if you end up with a similar fault don’t discount the LCM as in my case it was a 14 year old pcb that just went buggered .

 

[E86]

Thanks for coming back with the update. Well done for getting to the bottom of the problem, you did well to find the fault.

Have you got any photos of the failed LCM?