Ducati ST4S Owner's Manual page 132

Beam vertical setting (fig. 13.1 - fig. 13.2)
This function allows headlight beam height setting. To
enter this function, hold down button (B, see fig. 5.1) and
turn the key to ON; the display shows a value (fig. 13.2)
corresponding to beam position and the pilot light on the
display, indicating beam vertical setting mode (12, fig. 6)
comes on.
Headlight beam vertical adjustment range goes from 3 to
-3 for a total of 7 different positions (3, 2, 1, 0, -1, -2, -3).
E
fig. 13.1
22