audi a6 c6 taillight problem

A6 All/ S6 All
#1

hi. i am newto the forum. I diceded to start modding my car. I have the originial midline taillight. the taillight that is 7 pin and have the breakelight that is led but the rest of the lights is bulb. I started with the rear taillight but now that i have swapped the taillight the car starts to complain about that there is no taillight. i have checked the numbers in vag.com system and added the 131072 code but still nothing. when i added the highline code it sucked the battery of the car in just 40 min of. is it possible to have an orignal code that is 0205041. isnt that to high from the start?
sorry for so many questions. I got info from v8a6 to write at this forum and ask about the problem. here is the link to the new taillight.

https://www.sw-tuning.de/en/SW-Celis-LED-taillights-Audi-A6-Sedan-04-08-black-smoke-Lightbar-for-7Pin-Series-LED::34565.html?MODsid=b04e1f9166b462e8ac1b87fb92f47851

Best regards

#2

Hey!

Thanks for joining AR!. Hopefully someone here can help you out.

First step, you should contact the supplier. For sure, they will have done tests before on different models, so they may know root cause of the problem. Also, they may have a work-around.

So, reading the product listing, it states a couple times NO BULBS

suitable for 7-pin connector series LED taillights. no tail lights bulbs

ONLY for models with LED taillights series of work

So, they may just tell you, too bad, it wont work on your car. But anyway, best to start with them.

When I did LEDs on my C5 A6, I had to put a resistor inline of one of the wires to get the ECU to realize there was a bulb at the end. I have a feeling, you may have to do something similar to get them to work. However, with seven wires you are going to have to figure out which ones need the resistor. Try and get as much info as possible from the vendor.

This is an example of a LED light kit sold with the resistors. You can also buy the resistors seperately
http://www.ebay.com/itm/2x-1156-7506-Red-LED-Bulb-60-3528-SMD-5007-67-Tail-Light-Lamp-w-Load-Resistors-/251586014902?pt=Motors_Car_Truck_Parts_Accessories&fits=Make%3AAudi|Model%3AA6&hash=item3a93b1eeb6&vxp=mtr

So, your next issue is the wire harness/clip. With the example below, they actually sell the resistors with an adapter for the clip on both ends. Obviously, this will not work for your application, but will show you kind of what you need.
http://www.ebay.com/itm/2x-9005-HB3-22W-Cree-LED-Fog-Daytime-Running-Head-Lights-w-Load-Resistors-/121226575346?pt=Motors_Car_Truck_Parts_Accessories&fits=Make%3AAudi|Model%3AA6&hash=item1c39aabdf2&vxp=mtr

If you have an electrician buddy, he could probably sort the whole thing out for you by testing each wire, and then making an adapter with the resistors built in. He would need two more clips, one from each end.

So, try the vendor first. If they say they cant help, then youll have to figure out if it is worth it to pursue further.

There might be a vagcom fix for this, but I have no info on that. Maybe someone else will provide info if there is one.

#3

Hi i contacted them before buying it and send the info of the car and they said that it was the right taillight so i orderd it from them but now that i dont work i contacted them again and they say that they cant help me because its the car thats wrong. they hade konda bad service. got mad because i asked them before ordering th ledlights.
i will check to minus the higline code at vag-com and see if it works or else i have to try the resistor.
best regards

#4

im and electrician but have not done cars before. im use to houses, computer / game electronics and use to be an engineer at ericsson network. so figuering the wire is a problem for me. I needed to ask because im not so good at cars and have never sat down to look at how the enginering and electrical is in cars. so this will be a project to fix. hope someone has a clue for me before i start so that it can be easily down.
thx

#5

Well, that is a bonus :slight_smile:

DISCLAIMER: I have never done this before and am not even an expert in this section. Proceed at your own risk.

As far as I know, the ECU expects to see a certain resistance that a bulb provides. Then, when it sees less than that with the LED, it assumes it is an open circuit with no resistance, and burnt out.

So, figure out which ones on your trailights now are LED and which are bulb. For example:

Brake lights: LED
Turn signal: BULB
Reverse: BULB
etc.

Those are just examples obviously.

After you have that, you need to add one of those resistors to each wire that connects to that bulb.

So hook up the original raillights, and then activate each of the functions one at a time (brake, turn signal, etc) for each of them that is bulb. When you activate one, you will have to check each of the 7 connections with a multimeter, to see which wires are activated when with that function. You will probably need a friend.

When you have all the wires marked, then you will need to add a resistor to each of them that is bulb.

On eBay, looks like they are using a 50w 80ohm resistor.
http://www.ebay.com/itm/One-Load-Resistor-LED-Bulb-Turn-Signal-Lights-Hyper-Flash-Fix-1-Piece-50w-8ohm-/281431014109?pt=Motors_Car_Truck_Parts_Accessories&fits=Make%3AAudi&hash=item4186987add&vxp=mtr

Order from them in China, or buy at your local hardware store.

Alternatively, you could try and get a wiring diagram for your car, and skip the testing. Or, visually trace the individual wires from the tail light, if that is possible.

This is what I had to do on my C5 A6, but I think there were only four wires. Yours is a bit more complicated.

I can’t guarantee that that will work, but that is what I would start with if I wanted to spend the time to make those work.

BTW, I saw those tail lights online, and thought they looked pretty cool. The only thing I didnt like is that the surround seems to be blacked out. Post some pics if you can. I’d like to see what they look like on the car.

#6

I did something similar for a friend on his A6. The issue is if it’s the break light as that’s hard to get the right resistor for as it changes when you hit the breaks. There are no coding abilities for something like this so just leave the stock code. The best way to test this is to remove your bulbs and put in resistors until you don’t get a code. The best results in got came from actually pulling one side of the break lights apart and putting the resistors inside the break light housing itself.

Of you tackle this let me know. I can look more for information I might have wrote down when I did it. I believe the 80 resistor is what’s going to give you the best results

#7

Good tips Justin

#8

i checked the cables and opened the light. there was som cunductors that didnt work so i have changed them and now the taillights work but when i hit the brakes as you say the car starts crying about the fault. do you still have the info about the resistor? best regards

#9

I think this may be the point where you are going to have to do a bit of trial and error

#10

yeah i think so to. i have orderd the resistors so hopefully i will recieve it during the week. then let the tryouts begin :smiley:

#11

nice! Let us know how it goes.

Also, when you have the time please post pics of your Audi collection in the New Member Intro thread.

http://audirevolution.net/forum/index.php?topic=2542.0

The rumor is you have some very nice cars to show off :slight_smile:

#12

i have played a little bit with the car taillight. after changing some of the small resistor on the board i changed the codeon the car to. i took the highline code away and the taillight didnt work so the i replaced the code once again with the highline and voila it works all of a sudden. there is only one problem now. if i start the car with my foot on the brake pedal the cars starts screaming that they is no brakelight but if i start the car without the foot on the brakepedal it doesnt scream the whole journey. little strange but thats the status right now.

#13

It’s doing its first check on voltage apon start up and within the first 30 seconds. After that time it isn’t doing another check. Maybe after 30 min or something it might check again. Lots of times when. You change stuff just reload the stock code to clear the systems. For the ecu you clear codes for other modules you just reset the same code.