Long story short, I acquired a 2004 GT a few months ago and it came with the Mazda KA300 iPod/iPhone module. However, I don't own or plan on having an iDevice so that connector is pretty useless to me. Since the KA300 hooks up straight at the back of the stock in-dash CD changer and I don't feel like spending extra on yet another module, my attempt is to mod the module so it would work with (3.5mm in my case) AUX-in signal.

I mapped the pins of the KA300 cable and used the following diagram on the iPod connector side from here: Apple iPod, iPhone (2g, 3g), iPad Dock connector pinout and connections @ pinouts.ru

Here's what the cable side plug (male) pinout of the KA300 looks like (would be mirror image on the KA300 box socket side):

When I only wired 2,3,4 (GND,Right,Left) I had a No Disc on the dash and certainly no audio. I suspect the female iPod to male 3.5mm grom cable I ordered is hooked up exactly like that as well as it doesn't work either even though it was supposed to before they pulled it from their site...

I ended up hooking up all GNDs together to the 3.5mm GND, as well as the left and right channels and I got EX on the dash and audio playing for 30s when I hit the CD button a second time. After it shuts/cuts off at 30s it is required to cycle inputs to get EX and the audio back. Pins 12 (Tx) and 13 (Rx) shouldn't matter here, as those would only be used for controlling the tracks and getting the track info displayed on the dash I believe. Pin 21 should be for enabling serial mode on the iDevice and I somehow doubt that one would have a feedback to the KA300 at the same time but it is possible. The 19/20 +12V pin is the one I suspect the KA300 might be using for some sort of monitoring, perhaps it needs some load (ie. resistance) on there?

If anyone has thoughts/ideas or experience with either the KA300 or iDevice interfaces and can shed some light, it will be much appreciated.

 

Nothing yet? If u have some info, please, i need your help! (Sorry, my english is so bad! XD)

 

I gave up on it, suspecting it might be my head unit as it has older firmware and from what I read there's no way to upgrade unless you replace the whole HU... As much as I didn't want to invest more into this I ended up get the auxmod as it was the cheaper alternative.