How do you disconnect the OnStar phone on a 2003 GMC Sierra?

To disconnect the OnStar phone in a 2003 GMC Sierra, start by locating the OnStar control panel, typically found on the overhead console. Press the OnStar button to access the menu, then follow the prompts to deactivate the service or disconnect the phone. Alternatively, you can remove the OnStar module, which is usually located under the dashboard or in the trunk, but this may require technical knowledge. For assistance, consult the owner's manual or contact OnStar customer support.