# Help With Stereo Install Please



## brooner (Mar 20, 2017)

Hi All,

Having just bought a TT, we decided that modernising the stereo would be a definate need job (seeing as bluetooth and USB's are requirements these days...)

Anyway, our TT has the standard Concert CD headunit, 6 disc changer and Bose system.

At the moment, Im having some issues trying to track down the correct harness to go from the standard wiring (only 2 connectors on it?) to an ISO connection.
I have been told by one company that there is not harness for our car, but another says there is.....

I have been pointed at the Connects2 CT53-AU03 http://www.connects2.co.uk/Product/ProductItem/CT53-AU03

Can someone who is more in the know advise if this is the correct harness, or point me at the correct one?

Thanks
Brooner


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## asahartz (May 24, 2014)

PC9-410 for a Bose system. https://www.nexxia.co.uk/product/audi-bose-active-system-lead-rca/PC9-410/

See the attached for wiring details.

Also information in this thread: http://www.ttforum.co.uk/forum/viewtopic.php?f=2&t=160192&start=240


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## brooner (Mar 20, 2017)

Awesome - thank you very much asahartz.

This is turning out to be way more complicated than first thought......and I still have to fit the damned thing!
Neither of the companies I have been speaking to about the interface harness have suggested harnesses with RCA plugs, and the Kenwood unit I hope to (eventually) install has the RCA outs on the back.

The first bonus was getting the dials pod out without breaking anything (except my patience)

Im going to have a plethora of interface harnesses.....well, two as I have put the order in for the Nexxia one

Just to sort out my own ignorance, the pdf says there is no brown ISO connector on the car's wiring loom, if the car didn't have the Bose system, would the brown plug connect to the upper ISO socket on the back of the standard head unit?


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## richardkhill (Jul 20, 2015)

Hi Brooner and welcome to the wonderful world of TT ownership!

Replacing the OEM HU is a little confusing, but there's a huge amount of info on here via the search function.

You don't mention whether you own a coupe or roadster as there are a couple of minor differences. I believe you'll lose use of the CD changer and the ability to fade front/rear but don't quote me on those.

Firstly you'll need some removal tools like these http://www.halfords.com/technology/car- ... eys-pc5-93

As you've said you have Bose, you will need a PC9-410 harness adaptor http://www.halfords.com/technology/car- ... ss-adaptor If you have a Coupe there's a good chance you'll lose front/rear fade.

You will also need an adaptor for the powered aerial http://www.halfords.com/technology/car- ... tor-pc5-52 If you intend to utilise DAB, you'll need a new DAB aerial as well.

You may also need an RCA ground loop isolator http://www.maplin.co.uk/p/ground-loop-isolator-vw43w if you get popping when you turn the HU on.

You will also need to source a switched live for the radio, most people use the bush-bar in the drivers footwell, with an inline fuse. You may also need to swap the red & yellow leads on the PC9-410 harness around.









It's an absolute ball ache getting all these wires tucked in behind the HU but there is some space right at the back of the console.

The new HU cage will be a Very tight fit in the aperture. You will need to be quite forceful to get it all the way in.

Just don't fully install the HU until you're 100% certain everything is doing what it's supposed to!!

As I said earlier, there is a huge amount of info on here. Do your homework, take it steady, and ask as many questions as you want. You don't have your home town in your Bio - you might find someone close who'll happily help for some beer vouchers!!

GOOD LUCK!


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## damien.wrl (Sep 20, 2009)

Or if you can't live with all the disco lights, there is a £50 box which gives you hands free and Bluetooth tunes on your oe HU


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## brooner (Mar 20, 2017)

Thanks for the comprehensive note richardkhill - the photo explaining the bus bar for the switched power is extremely helpful.
Most of the dash is out just now, and wont go back in until I have everything in place.

The Kenwood unit came with a DAB aerial, and the fitting kit has the radio amp.
I foolishly thought that the interface harness would be the savior but it appears there is much more required to sort this (and I thought fitting the dash cams was a bit of a chew!)

I live north of Aberdeen, near lovely roads and scenery. Didn't think mk1 TT's were too common round here but Im seeing heaps of them now!


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## asahartz (May 24, 2014)

brooner said:


> The Kenwood unit came with a DAB aerial, and the fitting kit has the radio amp.
> 
> I live north of Aberdeen, near lovely roads and scenery. Didn't think mk1 TT's were too common round here but Im seeing heaps of them now!


Be aware that the stick-on aerials are not up to much; I use a mag-mount (Sonichi from Halfords) which is pretty good.

Sadly DAB is a bit limited up in Scotland as Bauer & co didn't see fit to extend the D2 transmitter network up there. And most of the stations I want to hear are on D2!


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## richardkhill (Jul 20, 2015)

asahartz said:


> Be aware that the stick-on aerials are not up to much; I use a mag-mount (Sonichi from Halfords) which is pretty good.


Asahartz is right, those stick on DAB aerials are awful. The magnetic one from halfrauds works very well on the coupes. I fitted one of these on my roadster https://www.amazon.co.uk/Hama-Roof-Ante ... dab+aerial


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## milnei (Feb 28, 2017)

Also worth looking at www.dabonwheels.co.uk


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## brooner (Mar 20, 2017)

Indeed DAB coverage is not the best here, and the station I tend to listen to isn't on DAB, but wanted the functionality to future proof things


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## brooner (Mar 20, 2017)

AAAAAAAGGHHHHHHHH!!!!

this is doing my box in!

I have a multitude of lead and connectors (attempting to use the PC9-410), but no power to the unit - not a sausage (link or lorne)

there is a blue wire coming off the large red connector (which has the RCA's coming out of it) - is this the one that needs to be connected to the switched power??
Or as seems suggested in another thread, does this blue wire buddy up with the antenna wire coming off the Kenwood harness??

What am I missing or am I too bloody stupid to own this car?


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## brooner (Mar 20, 2017)

oh, and i tried swapping the red and yellow connectors over on the Kenwood harness (helpfully, they have put bullet connectors in for this purpose) but no change......


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## asahartz (May 24, 2014)

In your 2003 car you'll need to run a switched live from the busbar. I posted a guide to how to do this in the thread I mentioned above - http://www.ttforum.co.uk/forum/viewtopic.php?p=5024833#p5024833 HTH.


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## richardkhill (Jul 20, 2015)

The blue wire from the red connector is used to power the Bose amp.

You should have a coloured fly lead on the back of your HU which will be labeled either Amp or Aerial. You connect the blue lead from the large red connector & the blue wire from the pc9-50 aerial adapter to the HU fly lead.

Have you run a fused power lead from the 12v switched connected on the bush-bar? This needs to be connected to the HU power input. This becomes live when you turn the ignition on.

I can't remember exactly how i did mine, but I'm sure the red/yellow leads provide constant power for the HU memory.


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## brooner (Mar 20, 2017)

asahartz said:


> In your 2003 car you'll need to run a switched live from the busbar. I posted a guide to how to do this in the thread I mentioned above - http://www.ttforum.co.uk/forum/viewtopic.php?p=5024833#p5024833 HTH.


Thanks - I "think" i have the blue wire thing sorted (both connected to the 'ANT CONT' wire on the Kenwood harness)

The switched live has be confused a bit though. 
I see you used a relay - was this to do things more professionally or is it required?

To put the switched live in, do I need to splice this into the yellow wire with bullet connectors (battery wire) with a fused wire to the 75K connector on the bus bar and then connect the red wire (ignition wire) to one of the 3 red terminals next to 75K???

Apologies if Im being thick here, but not done anything like this before and dont want to blow anything / me up.


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## brooner (Mar 20, 2017)

Another thought strikes me - if I dont have the switched supply, will that by default mean the headunit will not have power? Or is the switched feed there to keep the settings on the headunit saved?


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## asahartz (May 24, 2014)

The permanent live keeps the settings. The switched live powers the head unit when the ignition is on. If you do it according to my post, it does it the proper Audi way where the radio stays on until you take the key out of the ignition.


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## brooner (Mar 20, 2017)

asahartz said:


> The permanent live keeps the settings. The switched live powers the head unit when the ignition is on. If you do it according to my post, it does it the proper Audi way where the radio stays on until you take the key out of the ignition.


Long shot, but do you have a wiring diagram?

Im not clear on how everything links together.


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## brooner (Mar 20, 2017)

Right, had a thought at about 5 this morning....

Sat down with the Kenwood book and looked at the wiring and may have sussed a couple of things out....

Hopefully the pictures a) work and b) make what Im talking about clear

First, I looked at the handy connection diagram on the original Concert HU
(tried to link photobucket - didnt work....)

Then looked at the Kenwood harness
(see pic below)

Ignore the lower half of the ISO connector as this will be for the speaker connections that we have established is not used on the Bose system

The thing that struck me is the power pins dont match up, so I wouldnt have had power anyway.
The yellow battery wire connect to the top right pin on the Kenwood harness (location A4) isnt used on the original unit, to match the the Concert HU this would need to be in the bottom left pin (location A7)

Soooo, we have 4 wires coming the Kenwood HU, and 5 used pins on the original unit.
My thought is, if I move the pins around on the Kenwood harness to suit the original Audi ISO connector.

My plan (which may be ill formed due to lack of sleep) is:
Kenwood Wire - Audi Connector (as per Concert wiring diagram)
Battery (Yellow Wire) - Us+ 
Earth (Black Wire) - Earth (no change)
Ignition (Red)- DWA-GND
Blue/White (Power Control) - K-Bus

I also plan to move the Bose amp wire from the big red connector to the Bose pin to neaten this up.

If I am right (which doesnt happen often) this should give me a working stereo which is properly wired into the car.....on the other hand, this could be a very costly mistake......

Whats the worst that can happen?


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## richardkhill (Jul 20, 2015)

Firstly; get some sleep. Your fatigue will cause you to make mistakes!

Secondly; have a read through Wilco's post viewtopic.php?f=2&t=1284482&hilit=powering+stereo&start=15 He raised similar questions.

I've got a busy day today, but if time allows I'll pull my HU this afternoon and take some photos for you.

Sleep Well!!


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## Wak (May 6, 2002)

On the fuse board is a fuse marked S-Contact fuse 10 









Use a piggy back for the switched live feed









You will get oem radio operation including staying on until you pull the key out of the ignition


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## asahartz (May 24, 2014)

brooner said:


> asahartz said:
> 
> 
> > The permanent live keeps the settings. The switched live powers the head unit when the ignition is on. If you do it according to my post, it does it the proper Audi way where the radio stays on until you take the key out of the ignition.
> ...


Referring you back to the PDF from Nexxia which explains how to do this (last page). The blue wire from the Kenwood links to the Bose amp to power it up.


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## brooner (Mar 20, 2017)

ok, following a meciocre round of golf, attempt 467......

for the record, my great plan earlier failed, still no power......

I also headed to Halfords to aquire yet another harness (PC9-410 & PC9-404) and what I think is the PC9-410 harness is different to the one supplied by Nexxia (which doesnt appear work, so I think I will return them)









So, to attempt to follow the tried and tested methods....however I have been struggling to get my head round the wiring of the relay - I have drawn a (very poor) diagram of how I think everything should be connected (see image below - I realise I have put PC9-404 on the diagram, I ment PC9-410)
Im basing this on using the cable supplied by Halfords as it would be easier to wire the relay up to it. (EDIT: any idea what the 2x grey connectors with female bullet connectors are for?)








Am I yet again barking up the wrong tree, or am I moving in the right direction? Or should I hand it over to a professional as I am beyond help.....

Im not totally useless, I managed to remove the dials to be sent away to get a new LCD fitted, and get them back in without any breakage!


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## Wak (May 6, 2002)

What are you trying to achieve using the s-contact to trigger a relay ?

A piggy back from the s contact fuse gives you a relay triggered feed . 
The piggy back can have its own fuse 7.5-10a and go straight to the switched radio feed it's really simple


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## brooner (Mar 20, 2017)

I think this is a symptom things not being quite how I initially thought and of reading too much when you have a little knowledge.

I have fitted a pair of dashcams so have a piggy back fuse already.

I take it then I can connect the red ignition wire from the harness to the S contact, and the yellow to the K75 terminal on the bus bar?

Any idea what the two grey wires with bullet connectors are for?

Many thanks for the comments and info so far, Im sorry Im just so thick.


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## brooner (Mar 20, 2017)

SUCCESS!!!

Wired to piggyback lead into the S-Contact fuse and the 75K terminal on the bus bar and she fired into life!

Much "fun" was had trying to get the cabling into the stereo, but got it sorted. Even managed to get the dash panel under the wheel back in !!

The HU is sitting slightly proud at one side, probably lack of space for the cabling, so will pop it out and try and tidy it up, once the skinned knuckles have healed.

Many thanks to those of you who provided info and advice


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## Wak (May 6, 2002)

I know you had a success but 1. The 75k is switch feed no? And 2.s-contact is switched feed as well.

I don't think any memory settings will be retained.

1. The radio loom has permanent feed I don't think you need the 75k just the normal loom will power the radio

The s-contact piggy back will switch it on and off you don't need a Buzbar takeoff


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## brooner (Mar 20, 2017)

The memory issue has shown up - wasn't sure if it was because the red & yellow wires on the Kenwood harness were the wrong way round (handy bullet connectors for sorting that)
Perhaps move the eyelet from the K75 feed to the one next to it (red) to make it a live feed? (was working on Yellow / yellow basis)
(pity if it is, means I have to take the f%$*&@?g panel off the dash again - ho hum....)

Still "testing" but the fact it works, plays and bluetooths is a step in the right direction.

Got a bit of a "turbine whine", I suspect I may not have installed the GLI correctly, or I need a 2nd one as I plugged in the RCA leads to both front and rear connections on the back of the HU

Anyway, working stereo and I didn't destroy the car - win win for me!


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## gotmashed (Mar 27, 2017)

Did you get the rear amp and sub working ok ? I had to rewire my new harness to get it to work,
I had sound coming from the rear speakers but they sounded shocking, 4 hrs of back and forth being given new harness's some with rca out puts and some with out, Turned out all i had to do was connect the blue amp wire to an ignition on the radio side, and not the blue wire coming off the radio, Not to mention the lack of power to new radio with the so called plug and play leads they sell [smiley=bigcry.gif]


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## brooner (Mar 20, 2017)

gotmashed said:


> Did you get the rear amp and sub working ok ? I had to rewire my new harness to get it to work,
> I had sound coming from the rear speakers but they sounded shocking, 4 hrs of back and forth being given new harness's some with rca out puts and some with out, Turned out all i had to do was connect the blue amp wire to an ignition on the radio side, and not the blue wire coming off the radio, Not to mention the lack of power to new radio with the so called plug and play leads they sell [smiley=bigcry.gif]


I have one harness being returned as it didn't work - the blue amp wire is connected to the one coming off the radio marked ANT along with the analogue radio amp (I picked this up from the forum here - if you have read the full thread you will see I was having "issues")


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## Archer23 (Nov 23, 2016)

Wak said:


> On the fuse board is a fuse marked S-Contact fuse 10
> 
> 
> 
> ...


Looking at using a piggy back for the switched live feed when I fit my aftermarket stereo. 
But what size/rating of cable would I then use to connect into this to run it to the back of the stereo - i.e. 1mm 16.5A rated or 1.5mm 21A rated or larger?


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## HairyHamster (Apr 30, 2017)

If you don't have this sorted yet, drop me a pm as I have just replaced my BOSE Chorus head unit......it took a little head scratching but I got it working in the end. Now to chuck everything else in to improve the sound quality. Then I can get building the amp rack.

Sent magically from the dark corners of my mind using Tapatalk [FACE WITH TEARS OF JOY]


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## Wak (May 6, 2002)

Your stereo instructions should include the fuse ratings for the switched feed to tell you what fuse to use and add 3-5 amps to that to size the cable


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## LozTT03 (Sep 16, 2017)

Hi,

I have recently bought a 2003 Mk1 TT and have just installed a Kenwood BT502DAB as the standard Chorus tape player was stuck in SAFE mode. The installation wasn't simple but thanks to Autoleads PC9/401 its powered and is woking.

I have sound but the volume control goes up to the maximum of 35 and isn't the loudness/bass depth I expected from the Bose Amp. Have I missed something in the connections?

Thanks


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## LozTT03 (Sep 16, 2017)

Problem solved, turns out the PC9/401 was for Bose half amp which obviously wasn't fully powering the amp hence why it was so quiet...

I have discovered I have full Bose due to having Bose logos on the front speakers (found in any their thread on here). I have wired in a new Autoleads harness PC9/408 and the stereo finally works and is much louder now - happy days!

I bought the harness from Amazon on prime for about £32 whereas Halfords charge around £45!


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## Horlixx (Aug 13, 2017)

LozTT03 said:


> Problem solved, turns out the PC9/401 was for Bose half amp which obviously wasn't fully powering the amp hence why it was so quiet...
> 
> I have discovered I have full Bose due to having Bose logos on the front speakers (found in any their thread on here). I have wired in a new Autoleads harness PC9/408 and the stereo finally works and is much louder now - happy days!
> 
> I bought the harness from Amazon on prime for about £32 whereas Halfords charge around £45!


I think the 408 lead is for if your head unit doesn't have RCA outputs on the rear


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