Stereo Wiring Diagram For 99 Grand prix..Help plz!!

Hi, i need a wiring diagram for a 99 pontiac grand prix.. i looked for a wiring harness, but no one has them, they have them for every car but a grand prix, so i was just going to cut the plug off, and wire each wire up by hand. But the only problem is, there is no red wire, and all the wires are different and not striped. All there is for difference is 2 green wires for example... one is thicker then the other.. theres a thick yellow wire, and a thin yellow wire... but i dont want to cut the plug off untill i get a diagram to tell me what each wire is and what it does. Thank you. Hopefully someone can help me out!

This might help. I have the wiring diagrams but the color coding doesn't always match up between certain year model Grand Prixs.


http://mywebpages.comcast.net/alitaki/GrandPrix/audio.html

All GM cars since 1987 use the same harness at the radio. The only wiring differences involve the speaker hook-ups if you have the Bose system, which has a separate external amp.