An idea for the AUX input on the 2002 head unit
 

I want to listen to MP3s, but don't want to replace the head unit in my 2002 LX 2.0 because of aesthetic and other reasons. I would like to add an AUX input to the stock HU. For many cars, there are adaptors available that plug into the CD-changer connector and make the HU belive there is a CD-changer attached to it. But I couldn't find such adaptor for recent Mazdas.

I have some electronics experience and am not afraid of taking apart the radio and soldering.
The idea I want to try is to solder the AUX input in parallel to the CD player output, maybe using some resistors to make it work together. One more thing to make it work would be to record a special audio CD with dead silence on it. The radio would play it, but take the actual signal from the AUX input.
Before I search myself for the right point to connect : anybody out there tried this idea and has found this point already?

Why dont you try tapping into the input for the cassette player. Are you using that input? It sounds alot easier than what you are trying to do...

Using the input for cassete/MD is not easy at all. Noticed that when you press the "MD" button, nothing happens? The main module talks to the MD or cassete module over a serial link, and if it doesn't get the expected reply (which is kind of a secret code), it doesn't switch to that input. The same for CD-changers.
A small module that plugs into the cassete/MD slot and has an AUX input (or MP3 player?) would be really nice, but there is major hacking involved in doing this.
Oh, and the cassete module is available from Mazda for mere 287 Canadian (Minidisc for 800 something). Robbers.

How about getting the Mazda cassette adaptor for the HU and then getting a separate Mp3 player. Then attach it w/ a car kit. They also have wireless car kits available if you dont even want a tape player. It is a transmitter that u hook up to the mp3 player and it uses the car's antenna. I think u tune the radio to like 89.7 or somtehing.