2004 GMC Envoy Owner's Manual - Page 239

Radio Personalization If your vehicle has this feature, it allows the driver to return to the last used source: radio, cassette, or CD using the remote keyless entry transmitter. This feature can also store and recall AM and FM presets, volume, tone, and the last selected radio station. The number on the back of each transmitter, 1 or 2, corresponds to driver 1 or 2. If transmitter 1 is used to enter the vehicle, the last used audio source and/or settings set by driver 1 will be recalled. If transmitter 2 is used to enter the vehicle, the last used audio source and/or settings set by driver 2 will be recalled. Audio Steering Wheel Controls Theft-Deterrent Feature THEFTLOCK® is designed to discourage theft of your vehicle's radio. The feature works automatically by learning a portion of the Vehicle Identification Number (VIN). If the radio is moved to a different vehicle, it will not operate and LOCKED will appear on the display. When the radio and vehicle are turned off, the blinking red light indicates that THEFTLOCK® is armed. With THEFTLOCK® activated, the radio will not operate if stolen. Some audio controls can be adjusted at the steering wheel. They include the following: If your vehicle has OnStar®, press this button to interact with the OnStar® system. See the OnStar® manual provided with your vehicle for more information. If your vehicle does not have OnStar®, press this button to silence the system. Press it again, or any other radio button, to turn on the sound. g (OnStar/Voice Recognition): 3-119