ltooz_a6_a8_q7

If people still believe that you can embed a resistor inside a led bulb to kill the warning codes, they're totally naive.

TUNGSTEN bulb filament = cold 3 ohms, hot 60ohms, that's how the bulb doesn't blow up inside your lamp.

Ohm's law: P=VI=I*I*R=5w=12.5V*I=12.5V*12.5V/R =>R=12.5Vx12.5V/5W=31 ohms when hot.

You can't put any resistor inside any bulb to act cold = 3 ohms and change to 31 ohms when hot to please the bulb sensing system. If the try to put a 3 ohms inside a bulb, it will blow it up just like the picture you have.

To believe these bulbs exist is totally wrong, it doesn't matter what type of heat sink you put, it must be huge which never fit on a bulb.

Ohm's law again = I=V/R =12.5V/3ohms = 4.2A =>P=VI = 12.5Vx4.2A=52.5 W = where do you get a 52W 3 ohms resistor that's small and NOT hot?

Do I have to pay a lot for my LEDS that's designed correctly?

City light bulb
http://www.tomtop.com/car-accessorie...hite-k837.html

Driving LIght bulb

http://www.tomtop.com/car-accessorie...lamp-k780.html






4 - 20 cents PTC for 4 bulbs.

4 resistors - $2

Do it right and it doesn't cost much but the system is solid. If too lazy to do something, then just be happy with whatever they give you.

Cheers,

Louis

mishar

Does it trigger a code if led dies?

5W bulbs I tried have 68 LED's. I hope it should be enough for 5W without any additional resistance. That way all possible power is used for light not additional heat. They are many times brighter than 5W incandescent bulbs.

I was planing to use them as DRL since on 2005 A8 choice for DRL is low beam or fogs and I don't like either one of those. They where cheep and just as good. They may survive in opened air, but as parking light they lasted only 15 minutes. No code while they where working and code when they died.

ltooz_a6_a8_q7

The bulbs that use many little LEDS are to avoid. Typical LED draws 20-30mA and voltage drops across them is about 2-3V, Power consumption per LED is about 40-90mW . To add all these milliwatts to get to Watts is bad design.
The ones I'm using only have 5 bright SMD LEDS in them, the rest of the power are resistors. I tested with a volt meter and they only draw 250mA max at 12.5V.

Right now, the circuit is not designed to detect bulb failure because of the parallel loads of the bulbs. If all these LED bulbs use the correct LEDS, they should last the life of my car.

When a filament burnt out, it's totally open, there isn't a way to do this unless design a whole LED driver circuit as a buffer between bulb and the electrical system.

Cheers,

Louis

CMS062407

hmmm..i'm new to the A8---What in the world is the difference in "city lights" and "daytime running lights"?

I have heard of DRLS, and I can disable/enable them from the MMI...but I see nothing in rgards to "City Lights"


thanks!

soulminer

City lights are the internal ambient lights that come on in the foot-wells and door cards and pockets and under the rear view mirror, etc. You should find the settings under "internal lighting" in the MMI.

Vondera

I think the OP was actually asking about day time running lights. Interestingly, though, I just realized yesterday that the switch in the overhead console near the rear view mirror turns the city lights that you refer to (in the doors) on and off.

1Wasserwerks

Ahh really? Haha I never figured that out yet. More time is required with the owners manual for me I guess.

mishar

City lights are actually parking lights. Turn your light switch just one step and check what's on. You can also turn a turn signal left or right with engine off and leave that side of parking lights on. Not sure if anybody ever used it.

kbaum17

LOL. Believe me, you are normal. People on this site, even if they are from the same country as someone else who has posted, will use made up terms...terms that make no sense. There is no such thing (in the industry or otherwise) as "city lights". And, as you can tell, 5 different guys have 5 different understandings as to what is meant by it. it is ridiculous term.

and, yes, most people here are confusing "City lights" with DRL. To make the matter worse on this site (has been this way for years), the people here constantly confuse what is meant by DRL on the Audi A8 (D3).

Btw, the OP was NOT talking about the DRLs ...not even with all the confusion as to what is meant by DRLs on this site would a person be able to "tape over" the DRLs (which again, no one even is sure what they are.) But, you sure ain't taping over any reasonable explaination as to what a DRLs is on an Audi A8 (D3).

...likely some of the confusion comes from the fact that all these people here all of have different years and models codes of the A8...aaaaand also different MMI software version. All of which affect the ability and options regarding the DRLs.

We got one guy here going on and on about resistors and LEDs...with links that never worked, even back in the day when it was posted.

We got a guy or two here who think "City lights" are the interior lights. Heck, he may be correct....because "city lights" is a completely made up term, and to those that use made up terms, it means completely different things to different people.

The moral: there is no such thing as "city lights". Call them by there real names, whatever the names of those lights might be. Even Audi doesn't have names for some of these lights. Call them turn signal, parking lights, etc.

chokboywonda

The term of 'city lights' as described in one of the posts above is one of the themes you choose from for your interior lighting out of the list of Highway, cockpit, city or rear.

Outside of the car I know of parking lights (which you have on when you park and use the indicator selector to select the light so other motorists can see that side of the car sticking out)
And DRL, as the name suggests, is a daytime running light to give more awareness to other drivers and make you stand out more.