Unlock radio code for 1997 shilouette

It probably varies for each automobile and each radio.

I believe such "theft proof" radios have unique Unlock Code (when battery power is disconnected from radio then becomes non-functional until Unlock Code is reentered). If you have the original vehicle paperwork, and particularly the radio paper, you may find the unlock code. If not, suggest contacting the manufacturer dealer for advice; perhaps with VIN they can help. If not then suggest you start looking for replacement radio.