1999 GMC Envoy Owner's Manual - Page 148

yellowblue CLN: If this message appears on the display, the cassette tape player needs to be cleaned. It will still play tapes, but you should clean it as soon as possible to prevent damage to the tapes and player. See "Care of Your Cassette Tape Player" in the Index. After you clean the player, press and hold EJECT for five seconds to reset the CLN indicator. The radio will display --- to show the indicator was reset. CD Adapter Kits It is possible to use a CD adapter kit with your cassette tape player after activating the bypass feature on your tape player. To activate the bypass feature, use the following steps: 1. Turn the ignition to RUN or ACCESSORY. 2. Turn the radio off. 3. Press and hold the TAPE AUX button for five seconds. The tape symbol on the display will flash for two seconds, indicating the feature is active. 4. Insert the adapter. It will power up the radio and begin playing. This override routine will remain active until EJECT is pressed. Included with the AM-FM Stereo with Compact Disc Player are six Bose high performance speakers and a six channel Bose amplifier. Please see your dealer for details. AM-FM Stereo with Compact Disc Player (If Equipped) 3-12