Aftermarket stereo/iso adapter help needed!!


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Mar 5, 2010
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When I purchased my A3 it didnt have a stero fitted in it so priority was to put one in lol

Once fitted only the front speakers worked and to be honest dont sound very good! Im guessing I need an adapter to connect the amped rears and sub in the boot?

Which lead is it and where is best place to get or can I sort it any other way?

Ive added a couple pics of the loom to hopefully help!




Autoleads should be able to help, also you will need a signal booster for the radio to work properly, only a few quid on ebay.
as said you need a signal booster for the radio to work and you need a pc9-401 lead for it to work the rears as said mines from auto leads
Yea got the signal booster thing already from out the golf! Done a lil research seems could be a PC9-408 or PC9-401???
if you have the full bose setup amped front and rear you need the pc9-408
no don't think it is because the front work at the moment with just the standard iso plugged in so must be the 401? lol
You don't have Bose, as you have the brown front speaker harness shown in the pic. Bose has no speaker connections at the HU.
You just need the pc9-404 adapter:
Autoleads PC9-404 Audi Harness Adaptor (RCA, non-BOSE) £7.99 including VAT. PC9404. Buy discounted car audio online at In-Car Express

Bear in mind you will need to fade to rear quite a bit as the rear amp is only 2 x 20w and the fronts will be getting more than double that from the HU You can rewire the rears directly to the HU which will give better results but then the sub will struggle to even be heard.
So do the rca connecters link up to the back of the stereo then? Im going to be putting in my own sub anyway so possibly could be better to ignore getting harness and link straight to hu??
Yes id you are adding a sub then bypass all Audi wiring as it's shockingly bad. Get a male-female speaker harness and some speaker wire and rewire the rears to the HU, then use the sub RCA on the new HU to feed the new sub amp.

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