[rjeffery]

If you want to keep your factory headunit & steering controls and run your MP3 player through it, you can get an auxilliary input adapter. It converts the pin input on the back of the headunit to stereo RCA jacks to which you can connect your MP3 player via a RCA/headphone jack cord.

I did this on my 2002 and it works great. I dont know if they changed anything through the years (besides the looks), but if your radio has an AUX button it should work. I ran the wire down behind the dash, under the carpet, and up between the seats for a clean look. Really easy install.

I think the part # for the adapter is GMAUX, but you might want to verify that. I got mine at Tweeter for around $50, and the RCA/headphone cord from Radioshack for like $8.