I know I had a thread a while back asking for instructions for installing an AUX on a 2003 Bonne, but I finally figured it out, and figured I would share the info.
I saw mods that had other features, cars with XM could mod for AUX, cars with tape players could mod for AUX, but nothing that would work for my non-XM non-tape having car.
After looking through a bunch of forums, finally found some info on a Grand Am forums(can't find the link right now).
Any AUX cable should have three wires once you strip it, Left, Right and Ground. This picture shows how to ground it.
This view is from the top of the radio(with the cover off, obviously. The pins you're soldering to are parallel to the faceplate, to the right of the CD mechanism, when looking from the back:
You might want to take the CD mech out to get a better angle at it.
After that, you just run the cord through the side of the radio, and wherever you want in the car.
You need to have a CD in there, because you're "tricking" the radio into thinking the AUX audio is from a CD. I just burned a Cd with a 5 minute long MP3 file of no sound. I burned it in iTunes, and put "none" for the amount of time between tracks, so it doesn't interrupt. Works great.
Hopefully this helps anyone else in my situation, if you have questions, let me know.
Joe
03 Bonneville SE
EDIT: FYI, seems like this is the case on all Pontiac radios in this era(2000-2005ish). Obviously do this at your own risk, but seems simple.
