Ducati ST4s Owner's Manual page 134

Instrument panel (fig. 42)
Remove the headlamp fairing to reach the instrument
panel bulbs. Extract the lamp holder from behind the
instrument and pull out the bulb from its holder to
replace it. The bulb holder cables are numbered to avoid
confusion in the event more bulbs need replacing at the
same time. Be sure to match the numbers marked on
the connectors in the instrument panel.
Note
E
The bulb holders of the instrument panel lights have
a tang (A) to aid removal without risking to tear the
cables.
56
2
4
1
5
3
A
fig. 42
Turn indicators
The bulbs of the turn indicators are accessible after
removing the instrument panel side guards.
Front:
Turn the bulb holder (1, fig. 43.1) anticlockwise and
remove it from indicator body. Withdraw the burnt-out
bulb and replace it.
Refit the bulb holder with the round slot pointing upward
and turn it clockwise until it locks in place in the indicator
body.
OPEN
UPPER
CLOSED
LOWER
1
fig. 43.1