2004 Buick Century Owner's Manual - Page 147
2004 Buick Century Manual
Page 147 highlights
Setting the Time Press and hold H until the correct hour appears on the display. AM will appear for morning hours. Press and hold M until the correct minute appears on the display. The time may be set with the ignition on or off. To synchronize the time with an FM station broadcasting Radio Data System (RDS) information, press and hold H and M at the same time until TIME UPDATED appears on the display. If the time is not available from the station, NO UPDATE will appear on the display. RDS time is broadcast once a minute. Once you have tuned to an RDS broadcast station, it may take a few minutes for your time to update. Radio with CD Playing the Radio PWR (Power): Push this knob to turn the system on and off. VOL (Volume): Turn this knob to increase or to decrease the volume. 3-45