Dontheeagle GMCDC2W0749603 if the part number is 7 607 775 320 try code 2142 S/N: 90569379 ? < what is that serial from please. The code number for the stereo must be entered before the code number for the CD Changer can be entered, although they are both entered via the head unit by using different buttons Code Entry as Follows: Switch On Ignition (No Need To Start Engine) Press & Hold Preset " O " and Switch Radio On - Display Shows " SAFE " And Then Shows " 10 - - - - " Press preset " 1 " repeatedly for 1st Digit Press preset " 2 " repeatedly for 2nd Digit Press preset " 3 " repeatedly for 3rd Digit Press preset " 4 " repeatedly for 4th Digit If the correct code number is now shown Press & Hold Preset " O " Until Unit Beeps