Controls and features -> Clock for your BMW 3 Series 1997-2006

Clock  
83  
If you wish to have a permanent time  
display, you can make this adjustment  
in the car radio* display, refer to the  
Owner's Manual for Radio.  
In ignition key position 0: the time is  
displayed for a few seconds after you  
press the left button, refer to Odometer  
on page 80.  
You can set the time of day, and the  
display for the car radio, as follows.  
To adjust  
When the ignition key is in position 1 or  
higher, the time of day appears in the  
display.  
To set ahead: turn the right button to  
the right.  
To set back: turn the right button to the  
left.  
The adjustment speed will increase the  
longer you continue to hold the right  
button.  
To change the display mode: press the  
right button briefly.  
Every time you press the knob, the  
clock display alternates between the  
12-hour and 24-hour mode.