2000 GMC Safari Owner's Manual - Page 171

Rear Seat Audio (If Equipped) PWR: Press this button to turn the rear seat audio system on or off. The rear speakers will be muted when the power is turned on. You may operate the rear seat audio functions even when the primary radio power is off. VOL: Press this knob lightly so it extends. Turn the knob clockwise to increase volume and counterclockwise to decrease volume. Push the knob back into its stored position when you're not using it. The upper VOL knob controls the upper headphone and the lower VOL knob controls the lower headphone. This feature allows rear seat passengers to listen to any of the music sources including AM-FM, automatic tone control, cassette tapes and CDs. However, the rear seat passengers can only control the music sources that the front seat passengers are not listening to. For example, rear seat passengers may listen to a cassette tape through headphones while the driver listens to the radio through the front speakers. The rear seat passengers have control of the volume for each set of headphones. Be aware that the front seat audio controls always override the rear seat audio controls. Note that this feature is intended for rear seat passengers. AM-FM: Press this button to switch between AM, FM1 and FM2. If the front passengers are already listening to AM-FM, the rear seat audio controller will not switch between the bands and cannot change the frequency. 3-24