adding amplified subwoofer to factory system

my 2000 silverado ext cab has the delco am fm casette and cd player factory radio and front and rear speakers. I am adding a 10 inch sub woofer with seperate amplifier. In order to switch the amp on and off remotely I need to axcess a switched 12vdc lead at the radio....can anyone provide the color code for the radio harness?? THANK YOU>

There isnt a colored wire for the power source you need. The radio has an antena/remote pin going into the harness, but no wire comes out of it. Try to find that pin (one with a pin but no wire). Then while the radio is plugged in and turned on, test that pin with a test light. With the test light still touching that pin, turn off the ignision and open a door. The light should go out. You then need to somehow attach your amp's remote wire to that pin. Did that with mine, and it works great.