# 2004 Audi A4 aftermarket head unit install problems



## 03 (Feb 23, 2003)

Ok I have an '04 A4 with Symphony Sound and 6 disk in dash player. I just bought a new aftermarket headunit and wiring harness all that.
Well just spliced the wiring harness to the aftermarket headunit harness and pulled the OEM head out.
There's 3 clips that come out of the back of the OEM head, a black a brown and another black.
On the wiring harness that came for my model car only one of the black clips and the brown clip plug into this harness leaving one of the black ones just dangling.
From what I'm understanding is this extra black clip is for all the rear speakers so I'm only getting sound to the front speakers.
Do I have a wrong wirining harness? I ordered it from Crutchfield and told them all the details of my car and they said that's all I need, I'm just very frustrated right now.


----------



## 03 (Feb 23, 2003)

*Re: 2004 Audi A4 aftermarket head unit install problems (03)*

Here's pictures if it helps.
Stock head unit








Back of stock head unit








Factory wires coming out








Wiring harness








Not all the clips plug into the harness?


----------



## kwalton (Sep 3, 2001)

*Re: 2004 Audi A4 aftermarket head unit install problems (03)*

the additional black plug is the one you will need to hook up for the rear speakers. they are amped from the factory. i can't remember if they make a harness adapter for it but there is a way to do it without the adapter. can you give me a more up close pic of the plug? there may also be a diagram on the factory radio which may help as well.


----------



## 03 (Feb 23, 2003)

*Re: 2004 Audi A4 aftermarket head unit install problems (kwalton)*

This help?

























Thing is i've done plenty of head unit installs before just never ran into this problem.


----------



## kwalton (Sep 3, 2001)

*Re: 2004 Audi A4 aftermarket head unit install problems (03)*

the bottom plug in the diagram on the radio shows you what you need to do. the block to the right is where the wires are for the rear speakers. 
1. take the amp turn on from the aftermarket radio and tap it into to the wire with the symbol right next to the wire that says "com." 
2. take the the positive leads from the rear speakers on the aftermarket radio (should be green for the left and purplie for the right) and tap them into the "rr" for right rear and "lr" for the left rear. 
3. now take one of the negative leads from the rear speakers on the aftermakket radio (it does not matter which one) and tap it into the "com"
this will give the amp a signal to replay music, however, the rears will play a little louder. you can compensate for this with the fader control or you could also rewire and run new leads to the rear speakers to bypass the factory amp. 
*IMPORTANT* make sure that when tapping into that plug to pay attention to the diagram. you do not wanto to mess around with the "can" or "cd" part of the plug. you will only use the "line out" part. 
good luck and let me know if there is anything else.


----------



## 03 (Feb 23, 2003)

*Re: 2004 Audi A4 aftermarket head unit install problems (kwalton)*

Ok thanks a lot.
Yea I understood which part of the plug was for the rear speakers I just didn't know what to do with them.
I'll go give this a shot now.


----------



## 03 (Feb 23, 2003)

*Re: 2004 Audi A4 aftermarket head unit install problems (03)*

Ok got the head unit in working on all speakers, thanks a lot.
Now only problem is my car doesn't have an "ACC" setting its just, OFF, ON and Start.
So the head unit has constant power. Can't find anywhere to wire it to so that when you turn the car off the stereo turns off by itself.
Right now I just pull the face plate off to turn it off but I would like to get that corrected.


----------



## kwalton (Sep 3, 2001)

*Re: 2004 Audi A4 aftermarket head unit install problems (03)*

if you remove the drivers side underdash you can gain access to factory wiring. it's been a while so i don't relly remember if the newer year a4's have this but there should be a power distribution center above the dead pedal. you will need a meter to find out which one of the leads is switched 12v. if it is not there you will need to gain access to the igntion switch wiring to find you switched lead.


----------



## NesQuik (Nov 21, 2005)

*Re: 2004 Audi A4 aftermarket head unit install problems (kwalton)*

the WTF is an antenna, you need an after market antenna adapter to convert.


----------



## 03 (Feb 23, 2003)

*Re: 2004 Audi A4 aftermarket head unit install problems (NesQuik)*


_Quote, originally posted by *NesQuik* »_the WTF is an antenna, you need an after market antenna adapter to convert.









Any idea what or where to find this adapter cause my radio doesn't work I just realized. I get the really local stations that broadcast from like a few towns over but nothing from even NYC and I live 35 miles from the city.
It's not a huge deal but I would like to have my radio work if I could.


----------



## kwalton (Sep 3, 2001)

*Re: 2004 Audi A4 aftermarket head unit install problems (03)*

actually the WTF is the prewired sat input for the factory sat receiver. the antenna input is the one for the am and fm. you will need a 40-vw-53 which you can get at a best buy or circuit. there is also an amplified adapter but i can't remember the model number on it.


----------



## 03 (Feb 23, 2003)

*Re: 2004 Audi A4 aftermarket head unit install problems (kwalton)*

Yea I was guessing the WTF was satellite.
When I ordered the harness and dash kit from crutchfield it said I would need the 40-VW-12 for my car.








Which I'm using. The antenna wire is plugged in to the back of the receiver with this but just the stations aren't coming in anymore. Everything is staticy.


----------



## kwalton (Sep 3, 2001)

*Re: 2004 Audi A4 aftermarket head unit install problems (03)*

the 40-vw-53 is the amplified antenna adapter which will give you better reception.


----------



## 03 (Feb 23, 2003)

*Re: 2004 Audi A4 aftermarket head unit install problems (kwalton)*

Sweet thanks a lot.
Crutchfield is worthless.
I'll order that adapter asap. My iPod hook up and box/amp kit shoudl be in here tomorrow so I'm gunna wire that up over the weekend and throw all that stuff in.
When I get the antenna amp it'll finally all be done.
Thanks for all the help.


----------



## alicrefer (Dec 8, 2005)

You must use a powered antenna with bose (FUBU)adaptor AND it must be hooked up to the proper power lead in the harness or your aftermarket radio wont work


----------



## Anto1122 (Jun 17, 2021)

03 said:


> *Re: 2004 Audi A4 aftermarket head unit install problems (kwalton)*
> 
> This help?
> 
> ...


----------



## Anto1122 (Jun 17, 2021)

I have the same problem only i can't get any power what to ever to the cd player it won't even turn on


----------

