Xenon Headlights - Audi A4 - Aretas
On my A4 I noticed one headlight glass was fogged up. Later I realised the Xenon headlight on that side was not functioning. Further investigation showed that a plastic access hatch at the rear had broken.

Rather strangely, the light has now decided to work, and I have replaced the broken hatch to seal the unit again.

Could the fault simply be ingress of moisture, which a hot and dry day yesterday has dried out?

Or does anyone have any other ideas? The bulb is obviously okay, but is there any history of faulty ignition units? I am aware that they operate at a very high voltage, but I would have thought they would be sealed from any moistuer problems.

Thanks for any ideas.
Xenon Headlights - Audi A4 - Glaikit Wee Scunner {P}
I lost the rear cover on a Passat , bulb type,headlamp. It fogged up as you described.
I dried it out using a hairdrier and fitted a cover. Been all right since.
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I wasna fu but just had plenty.
Xenon Headlights - Audi A4 - Aretas
GWS - thanks, but I am really looking for any experience anyone has had on the effect of moisture on the Xenon high voltage system.
 

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