When ignition key H001 is turned as far as it will go (AVV) - pin 50 - a signal is sent to short-circuiting junction D097 B (pin 7). This distributes the signal to the coil contact of relay R20 inside the engine bay junction unit B001. The negative signal responsible for exciting coil R20 comes, on the other hand, from a contact inside the sensor unit on gearbox R20 (pin 10): this contact is open if the gearlever is not set to N or P. When the safety conditions are satisfied, the contact closes to earth and sends a negative signal to one coil terminal of R20. This acts together with a "50" signal on the other terminal to excite the coil and close the contact of R20. Via a line protected by F23, R20 then supplies the winding of starter motor A020.Pin 30 of starter motor A020 is also divided into 2 separate connectors: connector A receives a power supply directly from battery A001.The direct current generated by alternator A010 is sent from pin B+ to battery A001, through connector B of starter motor A020. If the alternator will not turn and thus charge the battery, an earth signal is sent from pin D+ to Body Computer M001 (pin 19 connector A).This is then connected via the CAN network to instrument panel E050, which displays an alternator fault message on the instrument panel display.The car is also equipped with a battery disconnection switch inside the maxifuse junction unit on battery B099.In case of accident, the car inhibits the power supply to the fuel pump by means of inertia switch I050. See E1010 SUPPLYThe control unit then forwards this negative signal to pin 34 of connector F leading to the coil of the above battery disconnector. The contact is thus opened to prevent distribution of a +30 supply from the battery to all electric components in the car.which, once open, causes an earth signal to be sent to boot control unit M063 (pin 33 connector F).