Flickering xenons

[mikeloadsasaabs]

My LH headlamp started flickering a couple of months ago - not so much a flicker, more a burst of brighter light and then a return to normal.  I assumed at first that it was the bulb, despite the fact that both bulbs were replaced within the last year in an attempt to improve the dismal dip. At that time, both were still working absolutely fine after 8 years. I have put the original 8-year old bulb in and it's doing the same. The RH is fine. Is there some sort of voltage-boosting gizmo that is unique to each side that could be packing up?

I doubt whether it's relevant but I went through a very deep puddle back in April, which doesn't seem to have affected any of the other electrics but I'm wondering if this particular part got splashed?

[Max Headroom]

Hello Mike. That sounds like an irritating problem.
I know very little about xenons, but from the symptoms I think I would firstly be looking at loose/corroding earths/bonding, and other loose connections or plugs.

I also understand that it is possible for some bulbs to be incorrectly fitted - not sure if this would be relevant in your case however, but maybe worth checking that hasn't happened, anyway

Edit:

Does it seem vibration related at all?

[sgould]

The voltage is increased by the ballast unit which is attached to the headlight.

There was also a batch of left hand headlamps around 2003/4that had a faulty pin in the connector. But I think this just caused the light to go out.

It's interesting that you raise this question.  My left hand headlamp has been flickering a bit for a long time.  I've not been sure whether it's been a change in intensity or the levellers operating oddly.  But last night the light suddenly went very bright when I drove over a rough patch, not long after I started the journey.

Mostly the flickering problems, before last night, seem to be in the initial stages while things are warming up.  After a minute, it all settles down and the beam is stable.

[mikeloadsasaabs]

I've not been sure whether it's been a change in intensity or the levellers operating oddly.  But last night the light suddenly went very bright when I drove over a rough patch, not long after I started the journey.

Normally it happens while I'm driving, which is why it took a long time pinning it down to the LH lamp. But the new ones I fitted were a good brand (Philips/Osram, can't remember as they were supplied in VW Audi packaging). 

It is sort of vibration related, in that it normally happens when I'm driving, but I finally got it to do it when I was parked up and then I could see which lamp it was. I'm happy that it's correctly installed, but I guess I could dig deeper and check various connections. Not easy as there isn't a lot of room in that area!

It seems a bit odd that the 8-year old, previously trouble-free bulb, is doing it as well. So if the only high-voltage units are on the bulb, then logically (unless I've been very unlucky with bulbs) it's a connection or earth problem. But I'm surprised it's getting brighter and not cutting out and then relighting if that's the case.

I'd like to get it fixed before someone lumps me for flashing my lights at them, they can be a bit pugnacious over here!

[mikeloadsasaabs]

Just tried a quick google and came up with a YouTube clip of a BMW with the same problem - turned out to be an earth problem with the rear lights. Might be worth a check!

Here's the link:

http://www.youtube.com/watch?v=QZU53F9TlIE

[Mr Linear]

My lights do exactly the same.

The right hand light hand light flickers just after the car is started then goes off for a second and back on again.

After warming up for a few minutes everything seems fine.

Could just be the ballast getting old as in a fluorescent tube light.

My understanding is that the ballast is incorporated in the base of the bulb....or am I wrong??

Mr L.

[Audax]

My understanding is that the ballast is incorporated in the base of the bulb....or am I wrong??

The ballast is integrated on the bulbs for the 9-5, the 9-3 doesn't have an incorporated ballast. For the original problem it could be indicative of a control module going bad (the things underneath the headlamps) as they regulate the voltage to the lamps, I think they need programming with Tech-2 also.

[sgould]

There's a ballast that fires the lamp built into the base.  But there's also an electronic unit built into the base of the headlamp that controls the other functions - xenon bulb, dipped beam screen, levelling motor.  The main beam halogen bulb is fed directly from the relay.

It is available as a separate part, if needed


Article : Electronic unit
PartNo : 12790592
Usage : Xenon
Order Quantity : 1

[Steve440]

I have retro fitted Zenons to my other car and I had the same problem just after I fitted them.

I turned the supply voltage was slightly down on one of the units due to a bad connection.

Steve

[mikeloadsasaabs]

But there's also an electronic unit built into the base of the headlamp that controls the other functions - xenon bulb, dipped beam screen, levelling motor. 

Is this for 9-5s as well as the 9-3 Will? I've found a new one of these on offer for 225 euros but it's too expensive for a punt on being the possible cause, I'll check the connections first.

[sgould]

Doh! I was looking at the 9-3 for someone else, but the principle is the same for the 9-5.  I'll check the part number (if i remember....) when i get home tomorrow lunchtime.

[sgould]

For the 2004 9-5


Article : Electronic unit
PartNo : 5408497
Order Quantity : 1

[Norfolk Jim]

Mike - does it make any difference if you switch off and on quickly with engine running?

Mine did a flicker once and one went out (prob about 4 - 5 months ago) and I just switched them off and on quickly - they did a couple of hiccups and all's been well since then. I drive with mine on all the while.

[collywobble]

Having never owned a car with xenon lights would anyone like to explain the advantages of them, given the high cost of replacing a bulb, and all the problems they seem to have with self levelling sensors etc, as against Osram Nightbreaker Plus at around £12 a pair?

[Audax]

against Osram Nightbreaker Plus at around £12 a pair?

Quite simply they are brighter and give a more uniform light when compared with halogen lamps.

Also, where can you get the Osrams for £12 a pair? I need a set as mine lasted about 18k then both failed within about a week of each other.