2002 GMC Sonoma Owner's Manual - Page 162

Setting the Clock for Systems with Radio Data System (RDS) Your radio may have a button marked with an H or HR to represent hours and an M, MN or MIN to represent minutes. Press and hold the hour button until the correct hour appears. AM or PM will appear on the display. Press and hold the minute button until the correct minute appears. The clock may be set with the ignition on or off. To set the clock to the time of an FM station broadcasting Radio Data System (RDS) information, press and hold the hour and minute buttons at the same time for two seconds until UPDATED and the clock symbol appears on the display. If the time is not available from the station, NO UPDAT will appear on the display instead. RDS clock time is broadcast once a minute. Once you have tuned to an RDS broadcast station, it may take a few minutes for your clock time to update. AM-FM Stereo Playing the Radio Power: Turn the VOLUME knob clockwise to turn the system on and counterclockwise to turn the system off. VOLUME: Turn this knob clockwise to increase volume. Turn it counterclockwise to decrease volume. RECALL: Pressing this knob will display the station being played or it will display the clock. Clock display is available with the ignition turned off. 3-8