Audi concert Aux in through CD changer, but can’t select Changer on head. Any ideas?

[eddie_baby]

Hi, I am trying to connect my mp3 player through the CD changer input of the stereo, the stereo input part is easy enough through the CD left and right input and CD ground which takes care of the audio side of things (CD-L, CD-R & S-GND), However how do I get the head unit to see that there is a CD changer attached ( or in this case not connected ) but at least so I select the input through the head unit so the sound can come through from the input. What I have to do is get the head unit to recognise the CD changer input even though there is not one connected, every time I press the CD button twice now and if there is no disc in the single disc slot it just says no disc, when there is a CD changer attached by pressing this button twice it should select the changer input, is there a pin I need to connect to another pin perhaps that would mimic if the changer was connected.

Here is a photo of my diagram of the head unit.

Any help would be greatly appreciated.

http://www.avforums.com/forums/car-...lect-changer-head-any-ideas.html#post10007820

 

[AndyMac]

No you can't just connect the audio leads and expect the HU to recognise it as a changer. You need a bunch of electronics on the data bus lines to fool the HU into thinking a changer is connected, something like an xcarlink or Dension ICELink.

 

[eddie_baby]

thanks Andy, I thought there may have been a simple cheap way around it rather than buying special leads. I did it on my megane no problem but it had an Aux selector.

the other thing is there seems to be a lot of leads for sale on the net claiming to conect an aux in to the concert head unit. there are leads with boxes on with electronics in im sure but there is also a lot of leads without any special boxes just plugs and wires like this one

http://www.lowcostcaraudio.co.uk/lc...+aux+input+audi+a2+a3+a4+a6+a8+tt/pid/9805884


http://www.dvbcaraudio.co.uk/connects-ct29au01-audi-input-free-delivery-p-4964.html

and i also come across another very simular one.

 

[AndyMac]

Yes those are purely AUX in leads, they won't work on any Audi HU that only has a CD changer as a means to get a signal in. Not totally sure what use they'd be on any HU TBH, surely the newer style HU's that have an AUX in option already have a jack on the front, but presumably this would be if you wanted the wiring hidden around the back.

 

[eddie_baby]

I don’t know, but could there be some way without getting to technical to mimic if a CD changer were attached, some sort of circuit loop or something by connecting various pins together?

Yes those are purely AUX in leads, they won't work on any Audi HU that only has a CD changer as a means to get a signal in. Not totally sure what use they'd be on any HU TBH, surely the newer style HU's that have an AUX in option already have a jack on the front, but presumably this would be if you wanted the wiring hidden around the back.

 

[AndyMac]

Yes you buy an xcarlink or ICELink, they do exactly that. Or you could reinvent the wheel and design and build a circuit that mimics the interface on an Audi CD changer, so that the databus sends the right signals to the HU and acts on the HU's instructions, but it's already been done for you. If it was as simple as looping a circuit then don't you think someone would have already done it?

 

[eddie_baby]

ordered one today, went for the conects 2 aux adapter