I've searched and searched, but haven't been able to find a perfect how-to on how to add an aux input (for mp3 player) to my Kia Sephia's factory stereo. Some have been close, but not quite perfect for my situation.

1st option: I've seen some write-ups where people have hacked into the head unit's (hu's) din connector for a factory cd-changer. I cannot simply buy an adapter b/c they don't make them for Kias. The write-ups I saw involved hacking into the left, right, and signal ground wires for the cd changer. Then they simply made a silent cd and put it in the cd changer. Here's my problem; I have the wiring for the cd changer, but not the cd changer itself. Since the hu can't detect a cd changer it will not allow me to select that mode. I don't have an actual picture of my din connector, but here is one that is very similar to mine. I'm 95% sure the pinout is the same.

My question is this; is there a way to trick the hu into thinking that a cd-changer is installed so that I could select that mode and therefore pick up the audio from the mp3 player?

2nd option: I read another write-up where someone soldered the L,R,& Ground wires directly to the audio processor chip on the main board of the hu. So I looked up the pinout for my audio processor chip and copied his procedure (which can be found here http://donn.dyndns.org/projects/carstereoinput/ ). It worked, well sort of... Here is the problem: When a song is playing everything sounds great, but when I try to adjust the volume or when the song changes I hear a lound popping sound; kind of like the sound an amp makes when its turned up really loud and you plug something into it. My question is this; is there a way to eliminate the popping sound? Do you think it could be a ground issue (I had the signal ground connected to a ground on the processor) or is it something else?

Thanks for any and all help. I'm trying to do this on the cheap (without buying a new stereo) and really trying to avoid an fm modulator (due to price and quality of sound).

Update: Today I tried a slightly different approach with the hu's audio processor chip and had some success, but one problem remains. Everything worked great when I connected my sister's mp3 player (A sanyo I think) and when I connected my laptop to the aux in that I soldered on. Volume was good with no popping sound from the speakers and the sound quality was great. The trouble is when I tried to connect my phone (an LG Dare) to play the music library it would make almost the same sort of popping sound as before whenever the song switched and after a couple of songs the the phone would just crash and go black. Thankfully I didn't fry my phone. I simply removed the battery, put it back in, and then it turned back on. I really wanted to use it as my mp3 player since I don't have the $ to go out and by a standalone mp3 player and the lappy is just to cumbersome/expensive to cart around. Does anyone know why the phone would experience this problem, but not my laptop or a standalone mp3 player? More importantly is there a way to fix it? For those of you who might need futher background info, here is the link to the datasheet for my audio processor chip. http://www.datasheetcatalog.com/data...TDA7313D.shtml Choose ST Microelectronics. I soldered the left signal to pin 17, the right to pin 7, and the ground to one that I found nearby on the board. The other end of the wire was then soldered to one of these buggers.