1996 GMC Sonoma Owner's Manual - Page 126

Disabling the Theft System 1. Press the 1 and 4 buttons together for five seconds with the ignition on but the radio off. SEC will appear on the display to show that the unit is in the secure mode. 2. Press SET and 000 will appear on the display. Understanding Radio Reception FM Stereo FM stereo will give you the best sound. But FM signals will reach only about 10 to 40 miles (16 to 65 km). Tall buildings or hills can interfere with FM signals, causing the sound to come and go. 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 SCAN to make the first digit appear. 4. Press SEEK right arrow or SEEK left arrow to make the next two digits agree with your code. The display will show the numbers you entered. 5. Press BAND and 000 will appear on the display. 6. Enter the second three digits of the code. The display will show the numbers you entered. 7. Press BAND. The disabling sequence was correct if --- shows on the display. The disabling sequence was incorrect if SEC shows on the display. 3-16