Hey every1! Last time I was here I burned my audio unit (recklessness). Since then I fixed the audio unit, and after some time of absence I returned to the AUX input problem. This time I had an idea to try and hack CD player to give me AUX input, and that's just what i did.
General idea is to play a "silent audio CD", and open audio channel on amplifier. Then you should connect an audio cable to the place where CD-unit sends signal to the amplifier.
To do this, take the audio cable and solder the respective wires to RCH, LCH, SGND pins on CN805. (pin layout is printed on PCB so it should be easy to figure out what is what).
CN805 is located at the bottom PCB of CD-player module (upper module of audio unit). You should unscrew and remove CD player box from CD unit to get more space for soldering.
After you do the work, connect your AUX device, play a "silent CD", and play your music from AUX device.
Voila!
This mod will NOT give you any control over your stock audio, but it WILL give you high quality audio input. AND it is the only way to get AUX input fro free on my 2003 Mazda 6.
I hope this will help.