Xenon Headlight Failure - Bulb Or Ballast???

parabolica · Post by **parabolica** » Sun Nov 03, 2019 10:27 pm

I removed my wheels; whilst it is possible you have such little room to work it would have made it impossible given the issues I ran into. I’m lucky to have a full workshop and jacks mind due.

I tried every trick to get the igniter back, including putting the bulb in the igniter first. Unfortunately not possible as the bulb sits in the light bracket in a specific way, plus if the igniter is already on you can’t access the spring clips that hold it in place.

What finally did the trick was fitting the bulb to the igniter out of the car a few times - there are two possible combinations for the bulb base to fit in the igniter (although only one works on the z4) and I found if I fitted the bulb a couple of times, the slots/holding mechanism freed up, so when I eventually fitted it the proper way, it just slid in and twisted.

ETA: cancel that; got into the car this morning and now I have the same issue again but this time on the passenger side. So it's either the igniter which I did swap over; or that bulb has also failed. Luckily I have another spare bulb, so will see what happens when I trouble shoot tonight.

parabolica · Post by **parabolica** » Tue Nov 05, 2019 9:23 pm

Ok final update from me; my ballast/control unit is fried - new one being delivered tomorrow. I did all the troubleshooting - swapping the igniters and bulbs over; I finally fixed the issue by replacing one of the bulbs. But that only lasted 12 hours when the other headlight started playing up. So t/s again and after swapping everything over and changing bulbs etc, the p/s still doesn't want to play, so it must be the control unit.

I can well believe this as there was a lot of moisture in my light the day after I had initially fixed things - my own fault as the back cover was off a long time in the cold and I was exuding a lot of body heat and breath trying to get the bloody things fixed.

Kern47 · Post by **Kern47** » Sun Dec 01, 2019 1:31 pm

Just changed my bulbs both sides.

The same problem still persists though... Bulb warning light and LH indicator on solid, despite the bulbs still lighting up fine....

So I guess that means it must be the igniter then, unless theres some sort of reset procedure or driving time required?

I did notice when I first went to test it after replacing the bulb that there did seem to be an 'electrical whine'/high pitched buzz coming from the suspect igniter/headlight unit. Never noticed it before, but is this a sign of a bad igniter?

biojo · Post by **biojo** » Mon Dec 02, 2019 9:56 am

you sure side light is working?

ph001 · Post by **ph001** » Mon Dec 02, 2019 11:18 am

Sounds like a ballast problem to me, if the bulbs fire up then usually the igniters are fine. This is on the premise you have fitted genuine oem quality bulbs, there are tons of cheap fakes on Ebay which are notorious for causing problems like this. Make sure you get them from a reputable seller.

Kern47 · Post by **Kern47** » Sat Dec 07, 2019 12:59 pm

So I changed the bulbs... Same problem. Changed the igniter... Same problem.

Anyone any ideas in the next thing I should be looking into? Wiring? Moisture ingress? Ballast?

mmm-five · Post by **mmm-five** » Sat Dec 07, 2019 2:22 pm

The ballast is a known failure point on these as any water dripping off the headlight sits nicely on top of the ballast - and the seal on the ballast eventually gives up.

Mine had about 200ml of water in and the board inside was rusted to f**k.

Got a new Hella one online for about £40 (example link, but same ballast is used on lots of marques). Not worth paying £20/30 for a 2nd hand unit.

Kern47 · Post by **Kern47** » Sun Feb 23, 2020 4:26 pm

An update on my lighting issues.

The initial problem I had turned out to be the angel eye bulb (must have thrown the warning before it actually blew). So I got that bulb changed once I finally saw that it was out. While I had the back off the headlight with my car sat on the drive awaiting the new bulb, it bucketed down with rain and filled my headlight

Soaked up most of the water and dried with hairdryer, no condensation, job done

until I was driving home at night and the main beam failed, throwing up a warning

Thankfully I had the spare igniter from my previous fault diagnosis, so swapped that and it was fixed

Until about 2 weeks later when I noticed the same headlight flicker and die

Just taken the headlight out to get to the ballast and there is corrosion on the connectors and inside when I came to open it up. Cleaned it up and put it back together. Same problem. Tried swapping the igniter again just to be sure but that didnt do anything.

So the light comes on for about 5/10 seconds, then starts to flicker, then dies and I get the bulb light on the dash. So I'm guessing this rules out the bulb itself? Meaning theres some component that's fried in the ballast. The Hella ones are about £160, but has anyone tried any of the cheaper alternatives from Ebay and can vouch for them before I splash out?

Hopefully no one has this same issue. And let it be a lesson... Dont get lazy and keep the headlight sealed whenever the car is left!

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