2005 Hyundai Sonata Owner's Manual - Page 144

FEATURES OF YOUR HYUNDAI 1 131 ! CAUTION: o Do not clean the inner side of the rear window glass with an abrasive type of glass cleaner or use a scraper to remove foreign deposits from the inner surface of the glass as this may cause damage to the antenna elements. o Avoid adding metallic coatings to the rear window glass, such as Ni, Cd, etc. These can disturb receiving AM and FM broadcast signals.