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Help with fitting a stereo please

Discussion in 'A3/S3/Sportback (8P Chassis)' started by Dazza0685, Aug 23, 2011.

  1. Dazza0685
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    Dazza0685 Member VCDS Map User

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    [Aug 23, 2011]
    Hi guys, im sure its been covered many times but i cannot find the info i need to solve my problem.

    I have a 2004 a3 with the concert headunit. I am trying to fit mty alpine unit in using the autoleades PC9 - 404 lead.
    I can get the radio to work and the unit to work on the front speakers but cannot get any sound from the rears..
    I am aware that the rears and the sub run off of an amplifier which is supplied via the 3rd plug on the lead, however all the leads i have seen are missing 2 wires from the centre part of the 3rd plug.. does anyone know what these wires are and how to get it working?

    Any help gretly appreciated.

    Thanks
    #1
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  3. Ash187
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    Ash187 Audi-Retrofits.co.uk Site Sponsor

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    [Aug 23, 2011]
    do you have bose in your car?
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  4. mrpeng
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    mrpeng 2.0T Quattro

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    [Aug 23, 2011]
    sounds like bose to me had same problem look on you head unit the audi 1 you will see on the diagram on top of the unit a switch symbol on the center block you need to get the amp wire to that from your new unit normally a blue wire with say scotch locks etc as you need to power the amp to get the rear speakers to work
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  5. Ash187
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    Ash187 Audi-Retrofits.co.uk Site Sponsor

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    [Aug 23, 2011]
    #4
  6. NHN
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    NHN Retrofitter - Audi - VW - Skoda - Seat Site Sponsor VCDS Map User

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    [Aug 23, 2011]
    Check wire to amp is connected to the headunit as that would run rears, if you had Bose then all the speakers run from the amp, no sound at all then.
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  7. Dazza0685
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    Dazza0685 Member VCDS Map User

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    [Aug 23, 2011]
    Ni, its not a bose set up and i have connected the amp signal wire but still nothing..
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  8. NHN
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    [Aug 23, 2011]
    Hold on a minute, just re-read your OP, so you havnt actually got the feed wires to the amp for the rears connected possibly, as that is probably why its not working, amp maybe powers up but no feeds wont help it much :)
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  9. Dazza0685
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    Dazza0685 Member VCDS Map User

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    [Aug 23, 2011]
    Every wire that is provided is connected... there are two wires on the original 3rd plug in the centre of the plug that dont seem to be on any aftermarket looms.. im guessing this is why i cannot power the amp up but i have no idea how to find out what these wires do?
    #8
  10. Dazza0685
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    Dazza0685 Member VCDS Map User

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    [Aug 23, 2011]
    [​IMG]
    That is the wiring diagram... the two wires are labelled 'CanL' & 'CanH'... im guessing they are to do with the canbus system but how do i get around it?
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  11. NHN
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    [Aug 23, 2011]
    I need to check wiring for that unit, but in meantime you could do a pin to pin check from old radio label on top, through adapter to the new head unit.
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  12. Dazza0685
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    Dazza0685 Member VCDS Map User

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    [Aug 23, 2011]
    I think that label is off a bose headunit but the two wires i have named are in the same position on mine.
    #11
  13. mathu
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    mathu Member

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    [Aug 23, 2011]
    I had the same problem when i tried to connect an aftermarket head unit to my A3 8P, when i purchased the head unit i also bought a wiring loom adapter that had RCA rear out which powered the amp for the sub and amp, these only provide about 40w to the rear so you have to adjust with the fader on the head unit to make it work properly.

    feel free to ask me any questions as it took me a while to get mine to work, but i have mine working now.
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  14. Dazza0685
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    Dazza0685 Member VCDS Map User

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    [Aug 24, 2011]
    Hi mathu.. do you have any more details on what you did to make it work as i bought the same lead as you it seems but i have had no luck yet.
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  15. mathu
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    mathu Member

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    [Aug 24, 2011]
    no problem m8, will go and take a few pics on how i have done them so that you will understand it easier
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  16. mathu
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    mathu Member

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    [Aug 24, 2011]
    here is how i have connected my head unit.

    this is the adapter that is connected to the standard Audi Harness, the important one that is needed for the amp and the rear speakers to work is the Red connector:
    [​IMG]

    The red connector gives out RCA connectors (Red and White), this needs to be connected to the Line Out (Rear) from your aftermarket head unit like the pictures below:
    [​IMG][​IMG]

    After connecting it up you will hear the rear speakers and the sub working but very faint this is because the harness usually give out 60W to the speakers but the RCA is only giving out about 40W to the amp and rear speakers so you need to adjust the fader to the rear until it sounds right:
    [​IMG]

    hope this helped, if you have any other questions please let me know.
    #15
  17. Dazza0685
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    Dazza0685 Member VCDS Map User

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    [Aug 25, 2011]
    Any luck with those photo's?
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  18. mathu
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    mathu Member

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    [Aug 25, 2011]
    yh I've posted it on here as a reply with photos but they not up yet for some reason, ill repost with external images links, might help.
    #17
  19. mathu
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    mathu Member

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    [Aug 25, 2011]
    this is the adapter that i have, it just plugs straight into the standard Audi Harness, the important one for you to get the rear speakers and the sub working is the red part:
    http://farm7.static.flickr.com/6200/6076945222_3da1b8741a_z.jpg
    t
    he red connecter powers the amp which powers up the rear speakers and the sub. from the connector you get RCA Jack connectors, you need to connect these to the Line Out (Rear) on the back of the head unit as seen the pic:
    http://farm7.static.flickr.com/6202/6076409961_c40434d930_z.jpg
    http://farm7.static.flickr.com/6196/6076945962_db939c063a_z.jpg

    t
    his is the only way I've managed to make the system work properly but the only downside is that the RCA jacks only provides 40W to the Rear Speakers and Amp, and the normal wiring harness give 60W to the front Speakers, to make it work properly you need to adjust the fader to the rear until it sounds right:
    http://farm7.static.flickr.com/6076/6076990444_8cd9d92f8b_z.jpg

    a
    nother thing i done is i have adjusted the volume on the head unit so that it is louder, i don't know if you head unit has this option but if it doesn't its not a big deal, all you have to do is turn the volume up to a higher level if needed.

    if you need any more help, please let me know.
    (p.s. sorry for bad quality image, its of my iPhone)
    #18
  20. Dazza0685
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    Dazza0685 Member VCDS Map User

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    [Aug 25, 2011]
    Ok thanks for that, i have just tried it and it does work.. Like you say it needs to be turned up a little louder but thats fine.
    Im sure there must be a better way somehow but for now this will work.
    Thanks for your help.
    #19
  21. mathu
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    mathu Member

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    [Aug 25, 2011]
    there is a better way, you need to rewire the rear speakers directly to the head unit but that means messing with the audi wiring which prob cause more problems in the future so ill jus leave it if i were u
    #20
  22. slepy
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    slepy Extremely smart and handsome person. VCDS Map User

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    [Aug 25, 2011]
    mathu
    RCA's don't give you 40Watts for speakers.
    All RCA's do is provide signal to the amplifier and amplifier gives power to the speakers.
    You need to adjust loudness with fader because of difference in power between the headunit and an amplifier.
    You can rewire rear speakers to power them from the headunit BUT you will not rewire the sub because it needs to be run from
    the amplifier. Best solution for this is to change the amplifier for a 5 channel one and wire all speakers from it, but for the standard audi speakers I wouldn't bother really.
    #21

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