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 devicesAir temperature sensor
Introduction
The engine control system on the diavel uses a sensor that measures air
temperature. This sensor has a resistance of
ntc type (negative temperature coefficient), that reduces its own value when the
temperature increases. The air
temperature sensor allows the engine control unit t ...
Refitting the rear wheel eccentric hub and rear wheel shaft
Refitting is the reverse of removal, with attention to the following points.
If the calliper bracket locating pin (14) was removed, apply the recommended
threadlocker on reassembly.
Tighten the pin (14) to the torque of 33 nm +/- 5% (sect. 3 - 3, Frame torque
settings).
If previously ...
Removal of the control unit
Loosen the screws (1) and remove the relay supporting bracket (2), disconnect
the connectors (3) and remove the control
unit (4) from the vehicle.
...