The main function of an electrical system of a diesel motor is to ignite the motor. The secondary function is to supply electricity for the lights, indicators and electric components of the vehicle. (Some of the most recent highway trucks also have electronic fuel controls. 

 

 

It is interesting to point out that alter you start a diesel motor, you do not need the battery anymore to continue going, because, unlike a gasoline motor, the combustión does not need an ignition system.