Where is valet button for 2002 Chevy trailblazer?

There isn't a dedicated "valet" button in a 2002 Chevy Trailblazer like some higher-end vehicles have. To achieve a similar effect (limiting access to certain vehicle functions), you would need to manually disable certain features or use the key to limit access. For example, you might remove the key from the ignition to prevent driving or hide the radio code if you want to prevent radio use.