Charging System: Description and Operation

The charging system is an integral part of the battery and starter systems. Since all of these systems work together, any diagnosis and testing should be done in conjunction.

The charging system is protected by a 10 gauge fusible link located in the All circuit. This fusible link is between the generator and the auxiliary jumper post, located on the left toe box.

The generator ground is provided through a case ground in the generator to its attaching bracket. This generator uses a voltage regulator internal to the generator.

When the vehicle is running, battery voltage is applied to the generator field terminal through the A142 circuit. This circuit is controlled by the contact side of the Automatic Shut Down (ASD) relay. The voltage regulated side of the generator field is controlled a voltage regulator, internal to the generator.

When there is current present in the field, and the rotor is turning, the stator in the generator produces a B+ voltage that is supplied to the battery through the A11 and A0 circuits. The All circuit is connected to the output terminal of the generator and goes through the auxiliary jumper post to the engine starter motor battery feed terminal. The A0 circuit is a direct feed line from the battery.

Circuit A16 is also an output from the generator. This is used to supply voltage to the contact sides of the radiator fan, and A/C compressor clutch relays. For additional information on A/C and radiator fan system operation, refer to group Air Conditioning-Heater.

A warning lamp, located in the message center, is used to alert the operator of a problem in the charging system. Circuit G12 connects between the generator and the message center. For additional information on the operation of the lamp, refer to group Message Center.

Grounding for the system is accomplished at the battery negative terminal. This ground attaches to the rear body ground, located at the left rear frame rail.