I have a stock Bose HU with Aux input, plus amplified 6x9's in the deck and a single 12 that gets RCA input and remote sig. from the bose amp wiring.
For the actual 3.5mm socket I just cracked open a old walkman I had in a drawer and unsoldered the headphone jack from the circuit board. Problems ive encountered with it is that you have to have a CD playing in the HU still for the head unit to switch over to the CD setting. (if you press CD play with no CD in the drive it doesnt do anything) This is because your just tapping into the wires that carry the audio from the CD drive inside the headunit to the processor. When it is playing the audio signal from the headphone jack the HU "thinks" it is actually coming from the CD player. Furthermore with this mod you cannot go back to playing CD's in the HU, the wires are cut...that option is gone. If your HU already does the E20 code this mod is useless for you. Mine spits the CD out randomly about once a week for the E20. My stock CD player wouldnt play for more than 3 seconds in between skipping so I didnt care about hacking it. Mine also locks the radio totally up to where I have to turn the car off and back on if I plug a charger into the Mp3 device while its plugged into the headphone jack.
ls1tech.com/forums/stereo-electronics/688297-how-you-can-add-aux-input-mp3-player-without-adapter.html
http://www.grandprix.net/forum/ubbth...=218416&page=1
