GM Service Manual Online
For 1990-2009 cars only

Press and hold HR until the correct hour appears on the display. Press and hold MN until the correct minute appears on the display. Display the time when the ignition is off by pressing HR or MN.

To synchronize the time with an FM station broadcasting Radio Data System (RDS) information, press and hold HR and MN at the same time until TIME UPDATED appears on the display. If the time is not available from the station, NO STATION TIME will appear on the display.

RDS time is broadcast once a minute. After tuning to an RDS broadcast station, it may take a few minutes for the time to update.