What adaptor do I need? + how/where to run ignition live from the fusebox.


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Sep 9, 2011
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Grays, Essex

My car 'would' have come with the stock Concert CD (Non bose) running front speakers.
+ stock amp running rear speakers and sub.

I bought the car with an aftermarket Sony stereo which im keeping, but with just radio 2 and front speakers it needs work..

Eventually/maybe I plan to run my own amp/sub. But first will see how I get on with my aftermarket Infinity door speakers running from the stereo and stock amp..

I found the following statement from AndyMac on a post sometime last year

As there is no ignition feed on the Audi loom, you need to either wire one in from the fusebox or pair the red and yellow wires together and turn the HU on/off manually

I dont want to spend out on Canbus and my power cables are currently bodged to work with me manually turning the HU on/off..

So my questions

1). Is there an adaptor I can buy to use with my Sony that will activate my rear amp and so activating my rear speakers/sub?

2). Where and how do I run the ignition live to the fuse box?

3). As AndyMac previously advised to me an another post - I bought CT27AA05 Aerial/Antenna VAG Active ISO Adaptor. He advised to run the blue wire from this adaptor to the 'power antenna lead' - Now this is a potenially stupid question, but on my stereo there are 2 blue wires hanging around seperate from the rest. One has a sticker says remote, the other antenna. I guess im to attach to this antenna wire?

1. You need the PC9-404 RCA input adapter to get the rear/sub amp connected then connect the blue flying lead on the adapter to the remote lead on the Sony. You will need to fade to rear to balance the sound as the rear amp is only 2 x 20w and the fronts will be getting 2 x 50w from the HU. Only solution is to rewire the rears directly to the HU, but then the stock sub will be overpowered, so maybe wait and do this when you add a proper sub.
2. There's no easy way to run a proper accessory feed to the HU on the B6 i.e. one that stays live until you pull the keys out. there's nothing on the fusebox, all the feeds are either perm live or go on/off with the ignition.
This thread details how to get a proper accessory feed, but you need to use a relay
3. Yes connect to the antenna lead - it's just a 12v feed to power the aerial ampwhich goes on/off with the HU
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Hi Andy

Im having a bit of trouble with this.

I think ive been given the wrong adapter but think I should be able to cut and shut it? Just need you to confirm if you could?



You can see the cars stock wiring coming from the dash.
The Sonys wiring and then part of the PC9-404 RCA input adapter in the middle of these (stock/sony) you suggested.

I was then left over with what look like RCAs and remote so I connected them up to the Sony.

Then some confusion as Im left with this seperate and unused blue?

And now the incorrect part as I can only assume these should plug in together but they dont fit.
Should I cut and shut these together and do away with the red blocks?

That is not the stock wiring coming from the dash. You need to trace it right back to inside the dash where the HU goes. Looks like someone has been busy either butchering the stock wiring or hopefully already installed a PC9-408 speaker input adapter. The red plug that doesn't fit the adapter is not the Audi plug, it's a standard ISO speaker connector. if you trace it back you will find another adapter probably with a foam covered hi-lo converter on it and then the original 20 pin mini ISO Audi plug (either blue/green/yellow or solid black). That's the connector the adapter plugs into.
Thanks Andy - you are right of course.
I took out the blower unit and found the rest and managed to take a lot out.

Here is a load I removed - any idea what it is/ was for?

it leads to this which I cant get any further access to?

Im guessing it was wiring for a 2 way radio or something??

Looking much neater now

Also any clue to the stray blue cable I was supplied with or is it not required?

Probably a handsfree kit that wasn't de-installed fully as it has fuses on it.
No the additional blue flying lead is so you can plug it into an ISO socket on the new HU if you don't have a flying lead to provide the feed.
Does it all work now?
Ive still not wired in an ignition live so none the wiser.
If I went for the 'bodge' and just blocked the red and yellow together for the manual turn on/off.

I may have dreamt this but im sure someone said that even if you did leave the stereo on, it will turn off itself after 10 mins or somthing?
Or will it just kill my batt over night?
Audi HU's auto switch off if they are only getting a perm live, aftermarket ones don't so it will drain the battery