@ Vitat: Yet, but it also says nothing about AUX. Probably when you buy the changer, you just plug it in and it works.

@ Brokly: Nothing, in any combination.

Anything else?
Thanks so far, Andrej

Here you are.
I am waiting for any suggestion, please.
Andrej

Yes, but my head unit does not have the function button. If it helps, i can take picture of it to show all the buttons that it has.
Thank you so far.
Andrej

It doesn't matter, I just want to use an input - sound left and right, nothing to display or control through the head unit. But how to enable aux function? Head unit has a button CD/AUX, but only CD works.
I guess I would need some electrical circuit, so that the head unit would think that it has a changer connected.

Any solution?
Thanks, Andrej

Hello!
I have a Pioneer head unit with CD and aux input. It is an original radio in my Honda Civic. The label says Pioneer DEH-M6006ZH.

I would like you to help me to connect a mp3 player through AUX port. I disassembled the unit and found marks on the board saying what the pins are (picture). So, what do I have to do to enable AUX button? Do I need an electrical circuit to convince the unit, that it has a changer plugged in?

Pins are:
1 BU
2 SWDACC
3 GND
4 SGND
5 RP
6 LP
7 BU
8 ILM
9 BUSP
10 BUSM
11 GND
12 NC
13 RM
14 LM

Please help me, I think it is possible.
Thank you, Andrej