factory audio system locked out

HELP

 i was trying to trouble shoot a  volume problem with my 98 tahoe factory audio system. i unplugged the power supply to the deck .when i plugged it back in the deck was locked out .i read the manual and found out i need a 3 digit security code to unlock the system. i purchased the 98 tahoe used and donot have the code. can anyone help me .        thanks in advance   

                                                                                   TINN

That used to happen to us all the time at Circuit City.  Contact a GM dealer with the VIN number of your vehicle, or even better, if you can remove the radio, get the serial number.  Ask for the parts department and they should be able to obtain the information for you. 

Note: some dealers actually charged us a research fee of $25.

This post and the procedures it describes might work for you, unless it's already been "locked out" by trying to unlock it too many times.

https://www.the12volt.com/installbay/forum_posts.asp?tid=4611

thanks for the info

                                           TINN