I have a Disco II 2001, Just installed a Kenwood KOS-A300 external media controler, got for less than US$80.dollars, the problem here is that I have yet to fool the Alpina head unit into thinking there is an external CD player connected.
Any ideas? if some knows how to please tell me. I can post picture later so you can see the end resuts in case you want to go same route

Please note the Wire # 19 on connector C1354 (upper far right on head unit) is currently not connected (CD-changer I-BUSS Communication link) I made a RCA famale jack out of wire #13 and #16 (CD-input left channel audio) wire 14 and 17 (CD- input right channel audio) this know connect an RCA cable from the head unit to the KOS A300 Media controler, #15 CD audio earth output conected to KOS A300 earth, and #20 CD permanent feed output connected to KOS A300 positive 12V input, number 18 is not used.

I looked all over, but found nothing yet.

 

i am in the same boat, i have a ipod controller that should just plug into where the CD changer harness go but it just does not seem to work. I have broken down and got a new head unit that should be here today from a Rover with a CD changer. If that works then i know its something with my head unit and I'll just dig into it and see if i can find any differences between the two. On the other hand if you find something out let me know.
I assume when you press the CD button nothing at all happens, like the button is not connected right?

 

yeap, nothing happens when you press the CD soft touch key.I will continue with my research to see if there is a way to fool the head unit. im there is, is just a matter of research, dedication and patience. I will let you know if i found anything.

 

Hi there,
It has been almost 10 years. Did you find out the fooling option?

 

Quite old thread...
The stock CD unit is an external CD player, does not need any fooling to recognize it is plugged-in; and the 'head' unit communicates data between them to handshake, tell how many discs are in there, their titles, times and contents. Plus, play, skip, stop, next... commands on that data line.
No simple jumper or bypassing will do the trick.
An elaborated programmed microcontroller simulating the data would be necessary; by reading and replicating such at power-up,

If the real plan is to add an auxiliar input; there is another way of doing it, by using sacrifiable input pins of the audio management integrated circuit, like AM, cassette.
How skilled are you in electronics and soldering like housefly shoes sized parts ?

 

This style aux input adapter? Maybe hardware has been updated? you lose the CD player though.....
https://www.ebay.com/itm/Land-Rover-...75.c1#viTabs_0

 

Thank you very much for your help. I know, there are couple of unit in the market, but I would like to use my own bluetooth unit (tune2air). Any way, it seems too much work for me. May be I can use cassette player for aux in.

 

it's super simple. Get the two metal tools for removing stock head unit, remove unit. Add the ebay adapter(will adapt the three smaller OEM stereo connectors) , plug in a 3.5mm bluetooth adapter. Test before re-install. Should take 20 minutes....

any bluetooth to RCA adapter should work.....(wired powered unit one may be better)..this is just example....
https://www.wish.com/product/5abc8ee..._BwE&share=web