Z4 Headlight Issues

12333 Views 7 Replies 4 Participants Last post by Vladi, Sep 27, 2013

ZPiggy

Discussion Starter · Aug 10, 2012

Hey Folks - new member and 1st post - hope you can help me out with the following problem:
The headlights on my 07 Z4 Coupe malfunction rather randomly, where one lamp goes out while the angel eyes stay on.

When this happens I pull over, and cycle the light switch and highbeams manually a number of times. With no rhyme or reason, one headlamp will quit, the other might turn off, or they both quit leaving only the angel eyes. Like flipping two coins trying to come-up both heads, they both eventually come back on, and I drive onwards.

Happens on long drives more frequently than short ones. I dont' think bumps in the road or moisture are factors here. Took it to the dealer and they couldn't replicate the issue... basically giving me the bird. Thinking it's a controller issue... anyone ideas on how to diagnose or where to look under the hood?

Many thanks in advance.

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Droptop85

· #2 · Aug 10, 2012

Could be the hid ballast or the bulb. More than likely it's a bad igniter in the bulb. I'd just order a new hid kit from ddm tuning. It's always nice to have back up parts when it comes to hid's. I've went through 3 ballasts so far.

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ZPiggy

Discussion Starter · #3 · Aug 13, 2012

Thanks for the input DropTop... the lights work fine most of the time, so I don't think it's the ballast or bulbs. I think I found an answer on an external site as follows:

"If the inoperative headlight varies from left to right, when you have the fault warning, we would suggest that the lighting control module may be at fault. The module is a part of the light switch, on the Z4 chassis. Therefore you must replace the complete assembly if either the switch or the module are faulty. The fault could also be in the individual light control units (I would not initially suspect the ignition elements, as the lights seem to fire-up just fine). However, it would not be as likely that both units are faulty and intermittent in the same way."

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rockababy

· #4 · Sep 26, 2013

Same issue here. What did you find out was the issue with the headlight?

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Vladi

· #5 · Sep 26, 2013 (Edited)

rockababy said:
Same issue here. What did you find out was the issue with the headlight?

My first suspect would be the ballasts. As mentionned above, if the lights fire fine, the ignitors are out of the question - their role in the whole story ends once the lights are on.
The problem being intermittent and more likely on long journeys makes me think there is bad connection somewhere, most probably between the ballasts and the headlights - once they become hot, the contact loosens even more.

The remedy is to take the lights out (bumper removal needed, unfortunatey), disconnect the ballasts and clean the contacts with fine grit sandpaper (1000 would do) and contact-cleaner spray. Or, at the worse case scennario, replace them - they are not so expensive at eBay - around USD 130 each.

Check out this thread:

http://www.bimmerfest.com/forums/showthread.php?t=719294

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ZPiggy

Discussion Starter · #6 · Sep 26, 2013

Hi Folks,

The dealer seems to have identified my issue... turns out the previous owner put in Xenon bulbs (made in Hungary), while my vehicle was not Xenon equipped as OEM. Hence the ballasts are not designed for Xenon and there appears to be a heating issue. So my choice is to buy new ballasts or replace the bulbs. Sucks for me either way.

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rockababy

· #7 · Sep 26, 2013

Oh man what a bummer! Well thanks for the heads up on that one!

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Vladi

· #8 · Sep 27, 2013

ZPiggy said:
Hi Folks,

The dealer seems to have identified my issue... turns out the previous owner put in Xenon bulbs (made in Hungary), while my vehicle was not Xenon equipped as OEM. Hence the ballasts are not designed for Xenon and there appears to be a heating issue. So my choice is to buy new ballasts or replace the bulbs. Sucks for me either way.

There's no such a thing like ballasts that are not designed for xenon bulbs.

Ballasts are the electronic modules that limit the current through the gas discharge of the xenon bulbs. In a vehicle xenon lighting system they also thansform the 12 V DC of the car's system into 85 V AC needed for the xenon bulbs to work, plus they generate the pulse for the ignitors needed to initiate the discharge through the bulbs. Some manufacturers combine the ballastand the ignitor in one box. All this is essential for the xenon lights to operate. And none of those (ballast and ignitor) is needed for a halogen (or other incadescent) bulbs - those need only 12 V DC to operate and take it directly from the car's system. So if you have halogen bulbs, you don't have ballasts and ignitors. If you have xenon bulbs, you do have ballasts (OEM or after-market). So your explanation of the problem observed does not sound very logical. :dunno:

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