Set Hour Mode
WARNING: This page is about a different car, the 2008 Chevrolet Malibu Classic. However, it is still accessible from the selected car via links, so may be relevant.
Press and hold the CLOCK button until an audible beep is heard. The radio displays the clock icon, the time and the text ADJ HOUR when it enters the Set Hour Mode. The hours will flash. Turn the ADJ KNOB in increments to adjust the hour. Pressing and releasing the CLOCK button exits the Set Hour Mode and enters the Set Minute Mode.