Heres what I did, Best solution by far if you have the knowledge
Heres what you need:
3.5mm jack-5 conductor normally closed(left and right input-left and right output and a common ground)
some small wire- I used wire from an ethernet cable
soldering iron and solder
Take out the cd player unit-there are 2 plugs-the one you are after is the bigger one
Its been a while since ive done this but i think its the last three wires on the plug on the side with a black wire-the rest are white (an easy way to check is to touch a wire to each wire while its on and you will hear a tap in the left or right speakers and then do a continuity for ground)
cut the wires going between the deck and mainboard and run them to your 3.5mm jack- the wires to the board go to input and the wires to the cd player go to output
mount you jack wherever you want- since mine didnt have a tape deck i mounted it on the front of the stereo
In the end heres what you end up with-with a cd playing, when you plug in a cable the sound will cut off, you can then plug that into your mp3 player for a crystal clear input that sounds great
