Charging System: Description and Operation

The charging system is an integral part of the battery and starting systems. Because all these systems work in conjunction, diagnose and test them together.

Circuit All connects to the generator output terminal and splices to join circuit A0. Circuit A0 connects to the battery. A fusible link between the battery and the generator in circuit All protects the charging system.

Circuit Z1 provides ground for the generator. Circuit Z1 grounds to the front the engine.

When the ignition switch is in either the START or RUN position, it connects battery voltage from circuit A1 to circuit A21. Circuit A21 supplies battery voltage to the coil side of the Automatic Shut Down (ASD) relay. The Powertrain Control Module (PCM) supplies ground for the coil side of the relay on circuit K51. Circuit K51 connects to cavity 51 of the PCM.

When the PCM grounds the ASD relay, contacts inside the relay close and connect circuit A14 from fuse 1 in the Power Distribution Center (PDC) to circuit A142. Circuit A142 splices to the generator field terminal.
The PCM has an internal voltage regulator that controls generator output. Circuit K2O connects to cavity 20 of the PCM. The PCM controls the generator field on circuit K2O.

When the engine operates and there is current in the generator field, the generator produces a B+ voltage. The generator supplies B+ voltage to the battery through the A11 and A0 circuits