1998 GMC Envoy Owner's Manual - Page 156

Disabling the Theft-Deterrent Feature Enter your secret code as follows; pause no more than 15 seconds between steps: 1. Turn the ignition to ACCESSORY or RUN. 2. Turn the radio off. To unlock a secured radio, see "Unlocking the Theft-Deterrent Feature After a Power Loss" earlier in this section. Understanding Radio Reception AM The range for most AM stations is greater than for FM, especially at night. The longer range, however, can cause stations to interfere with each other. AM can pick up noise from things like storms and power lines. Try reducing the treble to reduce this noise if you ever get it. 3. Press the 1 and 4 buttons together. Hold them down until SEC shows on the display. 4. Press MN and 000 will appear on the display. 5. Press MN again to make the last two digits agree with your code. 6. Press HR to make the first one or two digits agree with your code. 7. Press AM-FM after you have confirmed that the code matches the secret code you have written down. indicating that the radio is The display will show ---, no longer secured. If the code entered is incorrect, SEC will appear on the display. The radio will remain secured until the correct code is entered. When battery power is removed and later applied to a secured radio, the radio won't turn on and LOC will appear onthe display. FM Stereo FM stereo will give you the best sound, but FM signals will reach only about 10 to 40 miles (1 6 to 65 km). Tall buildings or hills can interfere with FM signals, causing the sound to come and go. Tips About Your Audio System Hearing damage from loud noise is almost undetectable until it is too late. Your hearing can adapt to higher volumes of sound. Sound that seems normal can be loud and harmful to your hearing. Take precautions by adjusting the volume control on your radio to a safe sound level before your hearing adapts to it. 3-23