I have a 2004 A4 Quattro convertible with headlight issues. The ballast have been replaced; the headlights have been replaced. Dealer says it's the igniters. The high beams work;low beams work for about 3 or 4 minutes then BOTH go out (dipped). Dealer wants to fix the headlights by replacing the headlight assembly on the driver's side, and replace both igniters- $2600. However,the more I read, the more I think this is Audi's problem. So how do I get Audi's attention about this? This is dangerous; I can't drive at night!

faullty headlight switch

Re: Condensation in Sienna Right Headlight.... - Toyota Sienna Forum

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Mar 10, 2009 - 15 posts - ‎9 authors Over the years, I was not a frequent visitor to SiennaClub...but when I did visit, it was... in the right, passenger-side xenon HID headlight of my 2004 Sienna...the light has... Check with your dealer and see if they can do anything about it. .... :o The HID bulb is also a PITA to remove because you are working ... Re: 2004 Sienna no brake lights, radio, heater/AC ...
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Toyota 2004 Sienna repair: Replacing HID ballast or ...

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May 1, 2010 - Replacing HID ballast or computer control lighting for the Headlight. Just got a ... Up until now, I did not know I had the option of seeing twice as far with Xenon. Also up to ... In the end after buttoning everything up, the light did work fine. .... Howdo you determine if you have a HID or non-HID light? Reply ...

there should be h 4 halogen bulbs in the car that do not require a ballast
ballasts are an after market fittment to run LED lights
if there is no requirement for the ballast then yes warranty is void
I suggest that you take it to an accredited auto electrician and discuss the problem as to why it would have a ballast and the potential wiring problems that could result

I would look this up in the owner's manual.

you have to loosen the whole headlight assembly to open the covers behind the lights to actually get to the bulbs. 4 screws, 2 are on the top of the assembly(phillips screws) the other two are hex and attach the bottom of the assembly to the car. somewhat difficult to see but look behind the assembly and down into the compartment and loosen the screws(they don't fully come out) just enough to pull the assembly out. open the black cover behind he low bean and there is the bulb

The ECU on my 2004 Sienna passenger HID light went bad due to the condensation in the light, or at least that's what it looked like when I opened it up. The ballast was all corroded. Anyway, I searched and searched online for a way to fix it without paying the dealer $900. I just fixed it today for $92. I got the replacement ballast brand new for $92 shipped from The Retrofit Source at this site: http://www.theretrofitsource.com/product_info.php?cPath=26&products_id=161
Then I searched for an online manual for 2004 Sienna, found that, and went through the procedure of partially removing the bumper cover, taking the screws for the light fixture out, turning it on it's side and replacing the ballast. It took me about 2 hours to do the whole job, and everything works fine.
By the way, I got the part from The Retrofit Source in about 2-3 days without paying any expedited shipping. They were extremely helpful on the phone, delivered earlier than I expected, and saved me $800!!

this most likely caused by a poor headlight ground, check around the headlight for any loose wiring that is screwed to the sheet metal of the car under the hood behind the headlight.

I have the same issue on my 2002 A4. According to my Audi dealer mechanic, there is a sensor on the front suspension that controls the angle of the headlight. Replacing this may resolve the issue.

AUDI A4- 2005. There is a technical service bulletin for this exact problem. take it to the dealer when this issue has happened while driving. During a daytime drive when cold see if you cant get the light to fail while circling your dealer. As soon as you pull into the service drive do not turn the car off do not flip the switch. I am an Audi Technician for a dealer in Birmingham alabama. Personally this is not my favorite repair to perform; What audi states is that if the bulb flickers the bulb should be replaced; if one side fails the bulb should be swapped left to right if the fault continues with the bulb the bulb is at fault; if the bulb is swapped and the bulb fails again on the same side it is the module. NOW: I currently am working on a 05 A4 that both bulbs both modules have been replaced and Audi has no clue what to advise on a repair. THIS IS AN ISSUE if it has happened to you ask if there is a TSB for this issue or try to find it for yourself.

Replace the gas cap and clear the fault code, most times this clears the issue with code P0455. If it does'nt then you will have to have test equipment hooked up by the dealer to find the leak.