I need to know what each color means on the existing radio stereo wires please... 1999 chev silverado.

I think this is the right table, but I don't know if it will display right. If not, go to http://www.installdr.com/InstallDocs/GM/PDF/460005.pdf

Typical GM Factory Typical New Radio
Pin What It Is In Dash Wire Color Equivalent Wire Color
A Left Front Spkr (-) Light Gray White w/ Black Stripe
B Left Front Spkr (+) Tan White
C Right Front Spkr (-) Light Green Gray w/ Black Stripe
D Right Front Spkr (+) Dark Green Gray
E Ground Wire Black Black
F Not Used
G Headlight Dimmer Wire Gray Orange (if available)
H Power Antenna Turn On Pink Blue
I +12 Volt Ignition Wire Yellow Red
J +12 Volt Battery Wire Orange Yellow
K Right Rear Spkr (-) Light Blue Purple w/ Black Stripe
L Right Rear Spkr (+) Dark Blue Purple
M Left Rear Spkr (-) Yellow Green w/ Black Stripe
N Left Rear Spkr (+) Brown Green