radio question

To the original poster, I drive a Peterbuilt locally so this may not apply to your radio. I press the volume control in and I get a one item menu item like "Bass 1/7". I can scroll through menu items by turning the volume control left or right. When I get to the "time" menu item, I press the volume control knob inward for 12 hour display [Am and Pm] or volume left or right to set 24 time display and press inward. Turn volume control knob to set the hour and press volume control knob inward. Turn volume control knob to set the minutes and press the volume control knob inward.
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.I don't know if this is any help. Good luck.