stereo problem

i wired a new head unit into my buick and i put all the wires in the right spot but for some reason the yellow ignition wire isnt hot when the vehicle is on. can someone with more knowledge the me help to identify the problem? i also checked all fo the fuses and had a few wires left over. black w/ white stripe, grey, skinny orange, dark green, and a second plug(smaller) had a brown w/white stripe and a blackw/ white stripe. :confused: