96 switching stereo wiring problems

hi guys,
please dont bite my head off, but im a newbie with this stuff, and very confused! :banghead:
i am currently switching my stereo on my 96 grand am and i am having trouble with the wiring. according to the diagram there are 2 yellows, brown, and gray's (i think). my problem is that the colors which have doubles are EXACT same colors, no stripes or anything. my new stereo only needs the 2 12 volt wires, ground, and left/right front/back, and says nothing about "illumination", or the other wires that do not seem necessary anymore. i hooked up the stereo and it doesnt light up, so i am dumbfounded! ... however i do not know what yellow is 12 volt, and which is the one for the speaker that is also yellow. i have given up for the night, and hope to come back to it tommorow with a good nights sleep. if anyone can help make sense, i am very grateful. even the smallest amount of helpful knowledge would be great!

Thank you very much

Did you purchase the GM wire harness connector for the radio. This will make the installation much easier the connector will also tell you witch wires to use. You can purchase the connector at Best Buy, or at any auto parts stores.