Circuit Operation

CIRCUIT 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 A11 connects to the generator output terminal and the 120 amp fuse in cavity 21/22 of the Power Distribution Center (PDC). Circuit A0 connects to the battery and the bus bar in the PDC that feeds circuit A11. Circuit Z1 provides ground for the generator.

When the ignition switch is in either the START or RUN position, it connects battery voltage from circuit A1 to circuit A21. Circuit A21 feeds circuit F18 through fuse 19 in the fuse block. Circuit F18 supplies power 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 C3 of the PCM.

When the PCM grounds the ASD relay, contacts inside the relay CLOSE and connect circuit A14 from fuse 17/18 in the PDC to circuit A142. Circuit A142 splices to supply system voltage to cavity C12 of the PCM. Circuit K72 from cavity C25 of PCM supplies current to the generator field terminal.

The PCM has an internal voltage regulator that controls generator output. Circuit K20 connects to cavity B10 of the PCM. The PCM controls the generator field on circuit K20.

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.