I know I created a thread already about this so the moderators don't yell at me. This is different in the aspect in that there is an easier way to diagnose if you have a flickering/failing low beam issue.

Now onto the details! If your A8 or relative A6 is having a flickering low beam xenon headlight issue, which then fails after a period of time, your most likely issue is the xenon ballast for the relevant headlight. I know this because I spent close to 2 hours diagnosing the issue without realizing that if it is the ballast issue, you will hear a buzzing noise for the working ballast and nothing, or intermittent buzzing, for the bad ballast. Once the issue has been found to be the xenon ballast any Audi dealership will try a charge you for a full bumper removal and blah, blah, blah, just to replace a xenon ballast which would take anyone, with basic mechanical skill max 2 hours to do themselves. This being said, before I purchased my car from the original owner, the passengers headlight failed (it failed the day I was suppose to make the purchase) and it was found to be the xenon ballast. The seller was very genuine and stated that he will not sell the car with a bad headlight due to it not originally being stated in the listing. He had it repaired, by an Audi dealer, and took a $1,200 loss to the original selling price of $9,100.

Now to more details about how to go about repairing a bad ballast yourself. The relevant side of failure has to have the wheel liner and thus bumper loosed to remove the headlight. To remove the whole bumper is a waste of time and not efficient if your a single man operation. Thus removing the nuts of the relevant side and all upper bumper screws (accessed under the hood), of headlight failure, is necessary. This will result in a loose bumper and access to remove the headlight. Here are some images of my repair: P.S. the first time I was diagnosing the issue I had to remove the bumper on both side thus it being fully removed, because I was swapping relevant components until the issue migrated to the opposite side.

First trying to find the source of the issue, i.e. swapping relevant components


Once it has been identified as a xenon ballast only one side needs to be loosed to access the headlight, shown below, notice how on side is sagging relative to the other.




i.e. for those who are extremely through, the passenger ballast didn't fail twice. I ended up swapping driver and passenger ballast until the issue migrated to the opposite side.

 

I am having the same issue do you have the part number please

 

5DV008290-00

https://www.europaparts.com/hid-ballast-4e0907476.html

 

Thanks for your reply. So this module is on the side of the headlight but i notice there is another module at the back of the headlight. What is that for

 

The one at the back is the control module for the whole headlight system. The part that I sent you is the ballast. Essentially it takes 12 volts and amplifies it to around 24,000 volts to ignite the gas in the bulb. If I remember correctly. To make sure your car has the same fault as mine, whichever headlight is at fault put you ear close to the headlight and listen for a light electrical buzzing noise. If it isn't present at the faulty headlight you need a ballast.

 

I just swapped out my HID bulbs last night, I removed the front wheels and the inner fender liners. This gave me great access to the bulb and ballast.

 

NOTE: I had an existing post, https://www.audiworld.com/forums/a8-...conds-2944290/ , but I figured this was appropriate as this is where I got the link (and it is the same recommendation to view this post I believe).


Resurrecting this post real quick - I have an issue with my headlight flickering and going out. I got the module listed in the link posted above (https://www.europaparts.com/hid-ballast-4e0907476.html) but that turned out to be, from what I can tell, the control module? There is a ballast of some kind inside the head light - on the Bentley Publishers diagram, it's #5 in the HID Headlamps exploded view, listed "Gas discharge lamp control module", and is part #4E0941471 (although on the module reads 5DD008319-50), as well as another one on the other side that is 4E0 907 813 (Bi-Xenon Headlight Pre-AFS Power Module). I replaced the 4E0 907 476 part, "Xenon Ballast HID Headlight Control Module", but this did not fix the flickering, nor the different color of the light as opposed to the working drivers side light.
However, messing around with the other two have it flickering less and NOT turning off entirely until a light off/on switch. So I've narrowed it down to those two. I'm thinking it's the one inside the headlamp assembly, the Gas Discharge Lamp Control Module (4E0 941 471 / 5DD008319-50). I am going to buy two new bulbs to replace the existing bulbs as well and make sure to get the same color.

Any ideas? Should I replace both the one inside the assembly and the pre-AFS power module? Or just the one inside the assembly? As well as the bulb, of course.

Thanks!

- Naudi Guy

 

That is quite unfortunate that it wasn't the same issue. Your best bet, before buying any new parts, is to label the old parts and swap from side to side until the issue migrates. This will tell you the exact issue and is what I had to do to find out the ballast was at fault. The total list of components are:

Ballast (Control Unit): 4E0907476
Light Power Module (aka: Licht Leisturssmodul): 4E0907813
Ignitor (square block on the back of the bulb): 4E0941471
Blub: N10445701

A loose ignitor can cause the issues you have described as well.

 

Okay, I have replaced the control unit already, and have now ordered a replacement ignitor (the square block on the back of the bulb) and a pair of new 4300K bulbs (swap them both out at the same time, so they're the same age + color + condition). I didn't order that "Pre-AFS" part - do you think that could at all be a culprit here? I can't really find much information about it, except that the AFS stands for Adaptive Frontlighting System or something along those lines. Having three different ballasts on each headlamp is very confusing!

The igniter / box on back of bulb: Bulbs (I went Kensun; I have the OEM type bulbs aka the OSRAM 4300K D2S' on a back order, but I've used Kensun on my Infiniti QX4 and they worked great; when the Kensuns start to dim, I'll have the backup OEM OSRAMs to replace them):
I went 4300k as the same from the factory as the light looks pretty good.. I had 6000K on my Infiniti and they were a little too "blue"-ish, while the 4300k seem to be a nice, crisp bright white.

Thank you!

 

im having this problem, my driver headlight is flickering then going off, but i am not hearing any sounds would it still be the ballast?