Ducati ST4s Owner's Manual page 135

Rear:
remove the screw (2, fig. 43.2) and detach the glass (3)
from the indicator body holder.
The bulb is of the banjo-type: press and rotate anti-
clockwise to remove; fit the spare bulb by pressing and
turning clockwise until it clicks.
Refit the glass sliding the small tab (A) into the suitable
slot in the indicator body and tighten the screw (2).
3
Number plate light
To expose the number plate bulb, withdraw the lamp
holder from the number plate holder, then extract the
bulb and replace it.
A
2
fig. 43.2
E
1
fig. 44.1
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