The negative cable, which is normally connected to the negative pole of the battery, is fastened to the crankcase. From here, the cable branches off and splits up within the electrical system to carry the ground connection to the different elements in the system.

The image shows the ground connection on left side of the engine crankcase.
The battery charging circuit and power distribution
Electrical power for lighting and signalling devicesDefault function (resetting ducati default parameters)
This function resets the parameters set by ducati for each riding style.
To access the function it is necessary to view the ""setting" menu", using
buttons (1) "s" or (2) "t" select the "riding
mode" function and press the reset button (3) to enter the following page.
Use button (1) "s" or ...
Residual range indication when the service is due
After resetting the first oil service warning (triggered at 1000 km), upon
every key-on the system displays the
indication of which type of service should be performed next (oil service or
desmo service) and the residual range.
A (green) warning (1) is activated for 2 seconds on every key-on ...
Removal of the steering head components
Note
All parts fitted to the top and bottom yokes, including the wiring and
control cables, can remain on the motorcycle
provided they do not hinder the following operations.
Loosen the screws (19) securing the supports (21) and (23) of splashguard
(22) to the air conveyors (t).
...