2002 GMC Envoy Owner's Manual - Page 224

Diversity Antenna System Your AM-FM antennas are located in the rear side windows. Be sure that the inside surfaces of the rear side windows are not scratched and that the lines on the glass are not damaged. If the inside surfaces are damaged, they could interfere with radio reception. Chime Level Adjustment The volume level of the vehicle's chimes can be controlled by the radio. To change the volume level, press and hold pushbutton six with the ignition on and the radio power off. The chime volume level will change from the normal level to loud, and LOUD will be displayed on the radio. To change back to the default or normal setting, press and hold pushbutton six again. The chime level will change from the loud level to normal, and NORMAL will be displayed. NOTICE: Do not try to clear frost or other material from the inside of the rear side windows with a razor blade or anything else that is sharp. This may affect your radio's ability to pick up stations clearly. The repairs wouldn't be covered by your warranty. If you choose to add an aftermarket cellular telephone to your vehicle, and the antenna needs to be attached to the glass, be sure that you do not damage the grid lines for the AM-FM antennas or place the cellular telephone antenna over the grid lines. 3-50