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  1. #1
    FactionOne's Avatar
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    S3 Seats in A3 - Airbag Light - Solved at last

    Right folks,

    OK, So in most (if not all) cases when you install S3 seats in an A3, you can't simply plug the airbags on the seats into the wiring on the car.

    Often the car has a three-wire firing mechanism and the airbags on the S3 seats are two wire. From what I can work out looking at the wiring diagrams there is perhaps a fundamental difference in the way the bags are fired - so if you choose to attempt to modifiy either end of the loom and connect the seats that's up to you. If both the bags in the seats fire and you're left covered in expensive leather/alcantara and foam, don't say I didn't warn you!

    So, without the airbags connected, the A3 will throw a fault code and the light on the dash is illuminated. This causes two things; firstly, it's damn annoying. Secondly, and perhaps more importantly, from what I can work out it means that the airbag controller won't even attempt to fire any of the other airbags in the car.

    This means that in an ideal world it would be possible to somehow 'confuse' the car into thinking that the seat airbags are connected, clear the fault code, and everything should be hunky-dory. No warning light and working dashboard airbags.

    OK, so ste_1210 got in touch with me as I'd done some investigating into this issue a while ago; and the other night we were chatting away with him in front of his car and me in front of a pile of wiring diagrams for the A3 and S3.

    We eventually decided that the 'resistor method' would be the most likely fix; and certainly the best thing to try first. For those who haven't seen the other threads, this involves bridging some of the wiring loom on the car with a resistor of a suitable value so that it thinks the airbags are present.

    After a bit of checking diagrams and discussion between us, we worked out the following...

    Each side (driver and passenger) has three wires in the plug for the seat.

    Driver:

    Yellow/Blue
    Yellow/Green
    Brown (Earth)

    Passenger:

    Yellow/Brown
    Yellow/Grey
    Brown (Earth)

    ...The Brown wire on each side does literally just go straight to earth, the remaining two feed back to the airbag controller.

    Based on that information we figured that the plan is to ignore the earth connection and bridge the other two on each side with a resistor.

    Based on previous discussion, 4.7Ω looked like the most likely value for the resistor; so ste_1210 got himself down to Maplin and picked up some resistors. He bridged the two pins in the plug with a 2W 4.7Ω resistor, and used VAG-COM to try to clear the fault code.

    ...The code cleared, the light went out!

    So, while some of the details may change depending upon the MY of your car, and indeed the seats (wiring colours etc.), the theory is sound and it is possible to get around this.

    I guess I have to make a disclaimer and say that if you want to try this procedure, it is of course at your own risk - especially if there are any variations on what we found; but we can say with confidence that it works - and I'm more than happy to try to help others out with any variations they may find.

    Regards,

    Rob.
    The truth they're trying to keep from you is that IPv6 has nothing to do with address space; we're actually running out of full stops.

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  3. #2
    FactionOne's Avatar
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    Also, it's worth noting that if you want to avoid getting the warning light in the first place (because you don't have VAG-COM to clear it with); you can swap the seats over and install the resistor with the battery on the car disconnected.

    That way when you reconnect the battery the car will never know the difference!

    ...Remember though, you may need radio codes and similar if you disconnect the battery.

    Regards,

    Rob.
    The truth they're trying to keep from you is that IPv6 has nothing to do with address space; we're actually running out of full stops.

  4. #3
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    id like to say a big thanks to rob for his help probly would of cut the wire on the dash if couldnt find a way around.
    and as said is tryed and tested on my own car and is working sweet
    2w resistor is needed as the lower watt resistors didnt work for some resson.
    always a good idea to insulate the resistor well incase it touches the seat and will earth it out and kick the airbag light back in which happed to me on testing you can buy the connector blocks from audi for £2 and make propper plugs which i have done saves alot off hassle and makes more dureable

    resistors can be bought from maplin for 40p

    so for less then £5 you can say bye bye to annoying airbag light

    hope this all this helps others

  5. #4
    FactionOne's Avatar
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    Teamwork mate!

    Regards,

    Rob.
    The truth they're trying to keep from you is that IPv6 has nothing to do with address space; we're actually running out of full stops.

  6. #5
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    I have this image in my mind with the two of you walking around the car with white coats and clip boards, discussing and recording findings.

    Nice write up, and cheers for the info.

  7. #6
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    Hi,this resistor is posiblle fit to A6 4B(c5)??I swap seats and I have now diferend conectors under seats and on the seats
    airbag light is now ON
    Thank you.Mike

  8. #7
    Cobra88's Avatar
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    Mine went straight in with no Airbag light problem.

    Guessing you mixed car & seats Pre/Post facelift ??

    I also checked wire colours first and where identical here
    but my seats are 2002 & car is 2001

    Regards
    Rick
    2004 Audi A4 (B6) 1.9Tdi 130 Sport (6) Avant in Dolphin Grey.
    18" S4 AVUS, RS4 Rear Roll Bar, Leather Alacantra Sport Seats, Shark Performance 170 Remap,
    BOSE, XtronsA4A double din, Full DIS, Autolocks & Alarm Chirp.
    Avant Sport 1.8T Valance with twin exit.


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    I am attempting the resistor method to fool the airbag system in thinking that all is okay. I know in your guide that you used 2w 4.7 ohm resistors but I have only been able to get 3w 4.7 ohm resistors do you think that these will still work?

  10. #9
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    Should still work. The resistance value is the same, just the power rating is different. Basically you'll be able to whack more current down your 3W resistor, but that shouldn't make any difference in this case

  11. #10
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    Another happy customer the 3w 4.7ohm resistors worked for me once the fault code was cleared

 

 

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