A4 Headlights

your bilbs probably blow due to the fact you touch the glass when fitting, natural oils in your skin cause hot spots on bulbs meaning the gas inside burns alot quicker than it should

Reply to
Anonymous
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your bilbs probably blow due to the fact you touch the glass when

I have no idea what this is in reference to, so please keep at least some context along with attributions in your posts.

2ndly, if this is in reference to a4 bulbs going out prematurely then your advice is almost certainly /NOT/ going to help. This is a known /very common/ problem with the a4's that I have been tracking/experimenting with. You don't seem to have this problem, but two things about this:
  1. replace the bulbs together. Keep the "survivor" bulb, but make sure that when one goes out you replace them both with new bulbs.
  2. I'm currently experimenting with my a4 which has two survivor bulbs. As I said elsewhere, I'll be sure to report back.
Reply to
Thomas G. Marshall

I have *NEVER* taken this approach with my 98.5 A4 and have replaced both headlights and one front turn signal light, each one at a time. The first headlight went out 1.5 yrs ago, the second about 6 months ago, the turn signal bulb a couple of months ago. I replaced each one only, not in pairs, and I wore gloves in the process. So far, no problems.

Reply to
KLS

KLS coughed up:

Ok, but again, that is to the side. That you have a car that does not exhibit the behavior I'm talking about does not mean that it is because you wear gloves.

I /always/ take extreme care anything glass that is supposed to get monstrously hot. And this happens every time.

*FURTHERMORE*, back when I had the dealership replacing these things under warranty, I was back all the time for a single bulb change. One time I stayed a cyclops for a long time, only out of laziness, and then my car lost the other as well. When I went to the dealership (still under warranty), the two bulbs lasted a much much longer time. When one died, and I replaced it, I was back to the ping-pong often-replacing of bulbs.

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.

Reply to
Thomas G. Marshall

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.

Ken

Reply to
KWS

KWS coughed up:

...[rip]...

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.
Reply to
Thomas G. Marshall

Surely the problem with Christmas tree lights is thet the bulbs are wired in series. In the olden days, as soon as one filament burn out, the whole chain goes open circuit and all the lights go out.

The bulb manufacturers came up with a cunning ruse (probably designed to sell more bulbs). Now when a filament goes, the bulb automatically goes short circuit, increasing the voltage (and hence, current) on all other bulbs. Now all of those bulbs are under greater stress, so the next weak one burns out .........

Of course, each set of bulbs should include one 'fuse' bulb (identified by a blob of white paint on the end) - effectively an ordinary bulb which doesn't have the 'short circuit' feature, but this requirement is not always adhered to.

Reply to
Peter Bell

Peter Bell coughed up:

The filiment is usually above an anti-fuse that heats up once the voltage increases (because of the broken filiment) and fuses closed. Ironically, I just read all about this.

The fuse bulb is no longer neccessary. Even the cheapest light sets I've seen have plugs with a special compartment for a couple of dinky Christmas tree light fuses.

Reply to
Thomas G. Marshall

You Guys need to get out more - lol.

Reply to
AustinMini.OsiTech.Net

AustinMini.OsiTech.Net coughed up:

True of anyone in usenet posting more than once, say, a month.

;)

Reply to
Thomas G. Marshall

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