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View Full Version : 2007 A6 C6 2.7tdi, Passenger Xenon Headlight - Strange Problem



NJD1977
25-10-2011, 10:04 AM
Hi, new to the forum, so hope you can help me.

My passenger side xenon headlight has a strange fault. When the car has been sat switched off overnight, or for a few minutes in a car park, both lights fire up absolutely fine and continue to stay on for the duration of my journey, however I noticed the other day that I switched my engine off at some traffic lights to save some fuel, and when I started the engine back up, the passenger light failed to fire, and the warning light came on the dash. I carried on driving for a while and then used the headlight switch in the car to turn the selector from "auto" to "on", and the light then fired up.

If I switch off the engine and fairly quickly proceed to switch it back on again, the light is either slow to fire (say 4-5 seconds), or doesn't fire at all. Once I switch if off and leave it a few minutes or overnight, then it fires absolutely fine. Again, once running, the light is perfect, no flickering and stays on for the duration of my journey.

Is this more likely to be a ballast or ignitor problem?

Are the ballast / ignitor changes a potential DIY job?

Anyone any idea on costs at the Dealer?

At the moment, I'm just living with it, because it basically doesn't cause me any problems, but I guess it may fail it's next MOT so would like to resolve before then.

Many thanks for any help.

NJD1977
25-10-2011, 07:27 PM
I think I might have an idea what the problem is. It basically seems to be that the bulb fails to ignite when it has been run for some time and is warm/hot. Once it has been left for a few minutes to cool down, it ignites fine again. This would tend to suggest that the bulb cathode is starting to have some build up which is perhaps preventing it from arcing when hot. So perhaps it is just the bulb after all. I would like to try swapping the 2 bulbs around to try to eliminate the ballast and ignitor from the equation, but really don't have any idea how to even access the bulbs on my car. I have tried some googling, but haven't found anything that helpful.

Does anyone know how to access and change HID xenon bulbs in an A6 C6?

Thanks