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A3 1.8T headunit issue

Discussion in 'In-Car Entertainment' started by Robbied, Jul 17, 2010.

  1. Robbied
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    Robbied New Member

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    [Jul 17, 2010]
    Hi all,

    Been reading the forum but couldnt find an exact solution, although im sure its there somewhere....!

    Replacing a concert headunit in my A3 '98 1.8T. No sub as standard in the car.

    Connected everything up including the remote output lead from the new kenwood, and have no sound at all. New headunit powers up and will find radio stations etc but no sound.

    Any ideas?!

    Thanks,

    Robbie
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  3. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Jul 17, 2010]
    All A3's have a sub. If it's a non Bose A3 then the sub also powers the rear speakers, so that is why you have no rears. As for the fronts have you connected the brown ISO front speaker loom to the HU? Is the Kenwood a fancy one where you can turn off the internal amp?
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  4. Robbied
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    Robbied New Member

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    [Jul 17, 2010]
    Didnt know that about the sub..! Unless its in the dash i havnt found it yet..!

    Thanks,

    Yep after reading through the forum i figured i'll have to re-wire the rears, no worries as i'll add my own sub/amp in the boot anyways,

    But figured i'd have fronts speakers.

    On the car side i have;

    One black ISO (connected direct to the kenwood patch lead)
    Green/Yellow/blue plug (connected to the PC9-401)
    Orange multi plug with just 1 pin (now going nowhere)
    Aerial and single spade (gnd from concert headunit)

    Thats it, no brown ISO on the car side. Wiring looks OEM and untouched from new...

    Help!?!
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  5. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Jul 17, 2010]
    If you have no brown ISO then you have the Bose upgrade. Look in the lefthand cubbyhole in the boot where the sub woofer sits. If it has 2 x 4" drivers then it's Bose, if it has 1 x 6.5" speaker then it's non Bose. If it is Bose then all the speakers are powered by the amp in the righthand cubbyhole, and the sub has it's own amp inside the tupperware enclosure. Check that 12v is getting to the flying lead on the PC9-401 when the HU is on as it sounds like neither amp is turning on with the HU. Also do not rewire the rears to the HU as it will fry the internal amp as all the Bose speakers are 1.5-2ohm impedance.
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  6. Robbied
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    Robbied New Member

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    [Jul 17, 2010]
    Hmmm, no sub?!! Just the CD changer on the left, and an empty space on the right!!

    Get the feeling i'll be starting again with this system?!
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  7. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Jul 17, 2010]
    Nothing under the changer, should look like this:
    [​IMG]
    Sounds like someone ripped out the system, either to sell it or to fit an aftermarket system, but if you went aftermarket there would be no need to remove the sub, just unplug it.
    #6
  8. Robbied
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    Robbied New Member

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    [Jul 18, 2010]
    Seems the amp is tucked away in there and powering the OEM speakers after all. Otherwise i guess they wouldnt be working at all. I will check my replacement headunit is giving out 12v and switching on the amp....

    Next question - if the OEM bose speakers are 2ohm impedance, what are my options should i want to replace them? Is it best to just wire new speakers direct from the new headunit or utilise the OEM amp in the boot to power new speakers from?

    Thanks, its not an obvious system to figure out and replace for someone new to the A3!
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  9. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Jul 18, 2010]
    Bypass everything Bose, it's pretty shyte and linking in to it just causes problems, by pass the amp and run new speakers from the HU
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  10. Robbied
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    Robbied New Member

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    [Jul 18, 2010]
    Understood - thanks for all the info on this!
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