KWS coughed up:
>
> "Thomas G. Marshall"
> . com> wrote in
> message news:jPrtd.3799$x26.2588@trndny03...

....[rip]...

>> The notion of replacing them two at a time came as a suggestion from
>> this website. I have verified that it works (as have others), and am
>> experimenting with dual survivors.
>
> I was getting a year of service out of the headlights on my 2000 A4,
> changing them one at a time. Usually, the second one would go within
> a month of the first.
>
> Two years ago, I changed both at the same time and haven't had to do
> so since. I am an electrical engineer and, frankly, I consider this a
> coincidence. Unless, of course, either I or someone else can come up
> with an explanation that makes logical sense.

Do *NOT* top post once others have bottom posted. It makes a freaking mess
and is impossible to properly rely to!

I feel your confusion in this matter. No one here, many with very learned
backgrounds, has offered up a satisfactory answer to this.

IRONICALLY, my brother worked for a car headlight division of sylvania. He
told me of how xenon's are peculiar in that they require circuitry to
radically ramp down the current to the bulbs since they are very much more
reverse-resistive than halogens when they warm up. They literally
accelerate out of control. I hope I got that right----I'm a software guy.

Point being, perhaps there is similar circuitry within the audi computer
system that is getting "fooled" by the lack of a bulb.

And *HE* doesn't understand what's going on here. It /cannot/ be at the
bulb level since each headlight is required by the DOT to be on a separate
circuit. Otherwise, one blown fuse would result in total blindness----not
great at 90 mph.

Perhaps they are on enough of the same circuit so that there is an increase
in voltage or current once one bulb blows. Similar to how Christmas tree
light companies warn against having too few bulbs working. The rest blow
quickly. So perhaps it's having just one bulb with excess current that is
burning the things out, even if the car is a cyclops for only a day.

*In any case*, I recommend you keep your survivor bulbs and try life with
two survivors.


--
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