Haunted Xenon headlight


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Jun 2, 2009
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Hi guys,

My research so far suggests that this is an increasingly common story and that Audi don't appear to know what's wrong.

I have the 2009 Black Edition A3 with the Xenon headlights that came as standard. She's not done much mileage so far in 5 years, and most of that was well within daylight hours so not much use of the headlights until winter time.

(If you've heard this one before you can skip down to: ** THIS BIT! ** further down)

Long story short, I've been having 'fun' with an errant headlight on the driver side.

It started to flicker (a random electrical type flicker, not timed flashing) and then would show up on the dash as right headlight dipped error. I'm out of warranty by this time anyway, so it goes into the dealer and has a 'faulty' lamp changed at a cost of £300-odd.

Now, I'm sure its not the lamp that is the fault in each case as, when switching the car on and putting the headlights on they work ok for a (seemingly random) while.

On two occasions, the fault occurred shortly after potential water exposure to the headlight area, one time with a good wash of windscreen (which washes the headlight too) and another time when I hit a very large puddle of water at speed. So I'm not discounting this being some kind of water/moisture problem at this stage.

Just been back into the dealer for the same fault and the lamp has been replaced under the warranty covering the lamp itself. Service dept. guy says, "If the bulb goes again, we'd be looking at replacing the whole headlight unit" but didn't mention the cost.
He also said the service chap had noticed some condensation inside the headlight that this "might be a factor". There is no condensation in the fully working headlight, so I guess there could be something in it.

The lamp 'failed' again on the way home that same weekend.

Now I'm starting to get concerned that this is going to cost a lot of money in new parts to eventually get to a hidden (and possibly simple) fault somewhere else.

** THIS BIT! **

I've been doing a fair bit of research here and around the 'net and have found various accounts of the similar problems and various 'fixes' that seemed to provide the solution as follows:

1. Replacement Lamp
2. Replacing both Xenon lamps (left and right) at the same time
3. Replacing the Ballast(s)
4. Checking/Replacing one or both of the levelling sensors - particularly a plastic arm (as these are apparently relatively easily damaged)

One or more of these fixes resulted in the poster following up with, "... no more problems!"

Several accounts suggested that this was a known fault with the Xenon lighting system, that Audi did not know what the fix was, and that pressure needed to be applied to Audi HQ to get them to sort it out and do a recall.

I'm not really sure where to go from here. I've had a look around underneath the car on the drive, but have struggled to even find a levelling sensor to check.

I'm open to (and appreciate) any information that might be of some use at this stage.

I've a few Q's:

1. Does the front bumper need to come off to remove the headlight unit for inspection?
2. Does the headlight unit have vents to allow condensation to dissipate?
3. Should I be able to see the levelling sensors without having the car up on a ramp and going underneath?
4. Is it possible there is some kind of moisture sensor in the lamp itself that shuts it off to prevent damage?
5. Should the car be shutting down the power to the lamp once it reports a fault with it on the dash? (Sometimes I swear it comes back on!)

I'm starting to think the Xenon headlights were a 'free' upgrade with the Black Edition because they were a tiny bit "experimental".
1. Yes front bumper needs to come off for headlight removal, really annoying as save for about 20mm they would come out with it still fitted.
2. Yes there should be a snorkel on the back. But if there's moisture it will take a long time to dry out and best to drive with headlights on all the time to heat the unit up.
3. No idea, they are on the strut somewhere though, so possible with the steering turned.
4. The ballast is sealed and the cable runs inside the headlight to the bulb and will have a modest amount of weatherproofing itself without being inside a sealed headlamp (so only the ballast is outside the headlight).
5. They normally only come back on when your turn the headlights fully off and back on again. Otherwise a fault usually cuts the power until that time.

By changing "lamp" do you mean the bulb?

Highly unlikely to be a levelling issue as that merely levels the bulb.

Flicker like this I would say the ballast is at fault, not the bulb as the ballast provides a stable voltage to the bulb, if it's not it could create this flicker problem. Have they changed the ballast? (this is the only bit that is exposed as it sits under the headlight, at least on the prefacelift they do).
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Thanks C_W.

Yes, sorry - Bulb. The ballast is on my "usual suspects" list but it has yet to be changed, as both times the dealer changed the bulb it was because, "The bulb came up on the computer as showing a fault".

I guess the problem with heating up the lens units (driving with lights on in the daytime) is that the bulb flickers out after a while so wouldn't continue to heat the enclosure effectively.

Interesting about the "snorkel" on the back. Thanks. I've left the car south facing on the drive today (it's fairly sunny) in the hope that the sun could do some magic and perhaps the damp air can escape that way.

Am I right in guessing that both the bulbs and ballasts are fully interchangeable for left and right lights? e.g. can be swapped from side to side?
I'd be checking for a poor earth point/connection.
Thanks guys.

Yes the old hairdryer trick did come to mind, but its tight as a ducks **** behind that headlamp unit - I wondered if I could effectively get the hot air to the right place. Presumably that means taking the whole unit out first?
I've done this on my car actually after a projector conversion on standard headlights; when they are put back together depending on he weather/humidity in the air at the time they can fog up badly over the next few days but it does dry out and then is ok after that. I have used a hair dryer to speed things up, just remove the main beam rear cover and stick the hairdryer in that (undo the dipped beam flap a little otherwise risk tripping the hairdryer out if there's too much air resistance).

I don't think the "computer" has the capacity to determine between the ballast of a bulb fault; it will more than likely just detect a fault on that circuit and say "bulb". My parents car (not an Audi) is doing the same thing come to think of it, the bulb will light ok for a short while, then flicker and go off and restart if you turn the lights off and back on. I'm going to change the ballast first - will let you know what happens.

As suggested, check the wiring but I doubt it will be that as the multiplugs are usually fairly water tight.
Ah OK, it's simpler than I thought then - was thinking about having to take bulbs out etc. for the hot air to get inside.

I'll be interested to see the results of your parents car fix.

Thanks c_w. :yes:
First off £300 to change a bulb :ohmy:
Just done mine and the replacement bulb was £60, took me about 20mins

With regards to the fault, first thing i'd do is swap the ballasts over from left to right and see if the fault moves, if it does you know 100% you have a faulty ballast.
If the fault remains then you know there is a fault with the wiring somewhere

You are going to get moisture inside the headlight, there's absolutely nothing we can do about that using a hair-drier is pretty pointless as it'll just accumulate again.
The system is designed and specified to work with a fair amount of moisture so it shouldn't make any difference to the system.

Have you checked the bulb/ballast yourself?
It's not a difficult job but it's really fiddly to get all 3 parts locked in place.
On my 8P there is a if the ballast is not installed correctly there is a tab that pops up to stop the connector from locating.
I had problems with mine after a mate helped me (he changed one side i did the other), he hadn't locked the ballast in place so the tab was sticking out slightly meaning the connector couldn't be 100% in position, result was a flickering light.

I'd remove the assembly, check that the connector and pins on the ballast are ok (i.e. not bent) then swap the bulb and ballast over the the otherside, see how you get on then
Thanks Gixerson.

Yeah, It would be awesome to switch the ballasts over. The results of that would be very interesting. Audi didn't to seem to care about the potential for a ballast problem, but one or two others have also pointed out that this could be the problem.

It's had some non-Audi bodyshop work in exactly that area and I've suspected for some time that something got winged in that process.

Did you have to remove the bumper to change the lamp? I can barely get my hand down behind the lamp unit to remove the rubber cover!

I'm in a bit of a bind in that I'm reliant on garages/dealers at the moment to do anything as I've not the tools to even remove the bumper (yet) so I may end up needing to find a local outfit that can investigate the whole thing and get the lowdown on it.

On the other hand, I may go all 'project' and get the tools required as I'm getting quite keen on a black optics RS3 grille upgrade. :)
It will be the ballast more than likely mate, as said swap them one side to the other and if it follows then bingo.

Sometimes they just fail it's reasonably common tbh.
Thanks Muzza80, it does look increasingly like that's the case. I just struggle with why a main dealer has so much trouble with the concept.
Been talking with Jody at MidlandVW today about pulling the bumper and taking a look at swapping the ballasts.

Can anyone confirm that they can definitely be swapped from left to right (i.e. exactly same part for left and right headlights) for my car? Details in signature.
OK, so update on the problem and (possibly) solution. I've had quite a few long trips without the headlight dropping out now and, so far as I can tell, it was a condensation problem. There was a patch of condensation inside the headlight lens to the point where it was forming actual drips of water (not just misting). Taking the totally cheap/lazy approach I decide to par the car the other way on the drive so that the front of the car was in the sun (albeit winter) for a couple of days.

Happy to report so far that both condensation and problem are gone for the time being.

Thanks for your help and advice guys. :yahoo:
Humm I have the same problem but mine's an 06 plate (I think it's a really rare upgrade for this age model). The passenger side bulb goes out often a short while after I've just turned them on and continues to do so no matter how many times I turn them off/on again. It's been on on and off problem for the 2 years I've had the car but sometimes it's fine; I do believe rain and water is playing a part as that's usually when the symptoms show (but can't be certain on that). I've never seen any condensation or anything inside the housing though?

I figure it's a loose connection or something but I know nothing about this stuff, I don't even know what a "ballast" is!

Any help appreciated as I really need to get it fixed.

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