Help needed with audio wiring please

[witm]

Hi everyone, I'll get straight to the point:

I have 2 front speakers, 2 rear speakers and a factory fitted subwoofer in my car - Audi A3 2002 (52).

Only the following wires are conected when I've taken the Audi cd player out:

BLACK 8 PIN CONNECTOR - I understand this; constant power to the unit from the battery.

• Ground
• UB+ (power coming IN via here, to power the unit)
  
• K-BUS (not bothered about this)
• DWA-GND (not bothered about this)

BROWN CONNECTOR - I understand this; the +ve and -ve terminals for the front two speakers. They are not amplified in anyway.

• LF +/-
• RF +/-

BLACK 20 PIN CONNECTOR - This is where I am confused!

• CAN-L (not bothered about this)
• CAN-M (not bothered about this)
• "+ Switch" (power going OUT from the unit, to power the speaker amps?)
  
• LR
• RR
• COM (two wires connected to this)

Someone please correct me if I am wrong but am I right to assume that

1) The rear of the car are all amplified so there needs to be power going to them for them to work ("+ Switch"). Does this mean the unit is the POWER SOURCE which powers the speaker amps?

2) The rear speakers are connected as LR(+)/COM(-) and RR(+)/COM(-) which is why there are two wires going into COM.

3) If this is the case how is the subwoofer connected. Could it be that I have mistaken an amplifier for a subwoofer? Or could it be that it is a subwoofer but is not connected at all?

4) Finally I have replaced the Audi Cd player with a Kenwood and I can power the unit using the black connector and correctly use the brown connector for the front speakers. However if I rewire the rear speakers correctly into the brown conneector also how do I send power to the speaker amps ie how do i send power down "+ Switch"

Any help would be greatly GREATLY appriciated.

[witm]

Just to add more info - I've just read on another post that:

It looks like the BOSE sound system has a total of 7 speakers:

2 tweeters in the front doors
2 low-mid in the front doors
2 low-mid in the rear doors
1 bass subwoofer in the boot

Well I have the exact same setup but my speaker grills do not have BOSE written on them.

Do I have the BOSE system or not? Now im REALY confused. Is there any other way to know for sure or should I be confident that I dont have BOSE simply because BOSE is not written on the speaker grills? This willl affect which wiring harness I get.

Also, I started this post AFTER I sold the original audi cd player so I dont know how to test if the tweeters/rear speakers/subwoofer are connected (I know the front are connect to the ususal pins on the brown connector)

Please any assistance anyone?

[T.sport]

Can you not just use the remote wire from the headunit which is for an amp?But to be honest i looked at re-wiring mine which is the same as yours (half amplified bose) and i opted for the correct cable adapters.A whole lot easier and better,cable costs around £20.If you want the cable number il dig it out for you

[witm]

Yeah the ref no. would be great. Im pretty sure my car is REAR amplified (as opposed to FULLY amplified) because the front speakers connect to the brown block which is standard.

So im pretty sure I need PC9-401 but, as i have two front tweeters, two front speakers, two rear amplified speakers and an amplified subwoofer, I do not know if the PC9-401 on its own will make all my speakers work!

How many speakers do you have? Is it exactly like mine? If so, did the PC9-401 send power and make send sound to all the rear speakers and sub aswell?

Many thanks.

[T.sport]

Yeah the lead number is PC9-401.The rear speaker cables are not in the front of the car,as the cables from the front ONLY go as far as the amp.Then from the amp to the speakers.My Audi head unit was the audi concert,which i assume is what you had.You should have- 2 front door speaker,2 front door tweeters,2 tweeters above the front seats on the door pillars,2 rear door speakers and the subwoofer.This cable re-routes the neccasary power to the amp in the back and is plug-n-play.You may need to swap the live & switch live cable,but that is very easy to do.The only exception to this rule is if you have 2 phono leads behind the original head unit,as this requires a different lead,but that is a rare one.Ive posted a e-bay link to the cable i bought,as the e-bayer was very good when i bought mine with quick delivery.Hope this helps.http://cgi.ebay.co.uk/Audi-A2-A3-A4-...4.c0.m14.l1262

[witm]

Hey thanks, my setup is exactly like yous and my Audi unit did not have the two phono leads at the back...so I gonna get the PC9-401 and give that a shot.

Btw your explanaation of the rear configuration and why i dont see the wiring for the back speakers has cleared up my confusion...i think i get it now. Thanks.

I have one final question you might know as you system is like mine. I only have wires going to the following pins on the black 'power' block:

• Ground
• UB+
• K-BUS
• DWA-GND

I know the UB+ is the Constant Live from the battery, but does that mean I dont have Switch Live?

To even get my Kenwood to turn on I have to connect the UB+ to 2 wires on the Kenwood (yellow and red). Do you know if this is correct? The Kenwood wiring allows me to do this easily by pluggin the red and yellow wire together and then accept the power through both.

Thanks for all your help.

[T.sport]

There is a switch there somewhere,but its not obvious.I cant remember what one it is,but i remember pulling my hair out for 10 mins before i realised what one it is.lol.Best way to find it is with a multimeter,and beware the switch-live wont lose its power until the key is REMOVED from the ignition.If you really cant find it,let me know and il pull my headunit out and let you know what i did(with the extra looms its a nightmare getting it back in)Where abouts in the country are you?

[hidnmine]

I've been trying to change the radio in my 2003 A3 all day.
Here's what (I think) I've found:
The front speakers are where you expect on the brown connector. The rear speaker connections LR and RR go to an amplifier in the sub box (the same amp drives the sub).
The head unit has power and ground connections as you say. I didn't find a switched input to the head unit. I assume that it's switched on and off via the Can bus. I added a wire to the ignition switch.
The switched live from the head unit to the sub switches on the sub. The sub has its own high current power connection; the one from the head unit just switches a relay.
I haven't used the PC9-401 adapter, but from what I've measured I don't think the radio will switch on/off with the ignition unless an additional connection is made.
One problem I still have is that radio reception is very weak. The aerial connection doesn't go to the whip on the roof, but to a "diversity unit" which switches the aerial betwen a number of inputs (?). There's an extra connector on the 'Concert' radio which I think controls this switch box. At the moment I don't know what to do to fix the radio reception unless I rewire the aerial on the roof to go direct??
One question: Before I removed the "Concert" radio, the subwoofer was so quiet I thought it was faulty. Is this normal?

Cheers
Andy

[T.sport]

The sub isnt very loud,so that is normal.I connected mine using the PC9-401,and my radio reception is excellent so i maybe it has an amplifier somewhere that the new harness powers up?

[witm]

T.Sport:

I like in Birmingham, West Midlands.

I've purshased the PC9-401 just so I hope its plug-and-play and I dont have to think about this anymore. If I had the time I would realy have liked to understand how the system is wired up but Im so busy with everything else the PC9-401 will have to do for now.

With regards to the Switch Live - The ONLY other wires are:

• K-BUS
• DWA-GND
• CAN-L
  
• CAN-M
  

So im going to assume Switch Live must be one of these, but as im getting the PC9-401 im gonna give up finding out which...i'll let my £20 do that job! LOL

Thanks for all your help.