1997 Buick Century Owner's Manual - Page 181

Backglass Antenna (If Equipped) Your AM-FM antenna is integrated with your rear window defogger, located in the rear window. Be sure that the inside surface the rear window is not of scratched and that the lines on the glass are not is damaged. If the inside surface damaged, it could interfere with radio reception. Because this antenna is built into your rear window, there is areduced risk of damage caused by car washes and vandals. If you choose to add a cellular telephone to your vehicle, and the antennaneeds to be attached to the glass, be sure that you do not damage the grid lines for the AM-FM antenna. There isenough space between the lines to attach a cellulartelephone antenna without interfering with radio reception. NOTICE: Do not try to clear frost or other material from the inside of the rear window witha razor blade or anything else that is sharp. This may damage the rear defogger grid and affect your radio's ability to pick up stations clearly. The repairs wouldn't be coveredby your warranty. 3-37