Starting and Charging Circuit Starting Operation

Voltage is applied at all times to the Ignition Switch from Fuse 6 through the RED (242) wire. When the Ignition Switch is turned to the Start position, voltage is then applied to the CRANK fuse through the YEL (5) wire. From the CRANK fuse, voltage is either applied to the Clutch Pedal Position Switch (Manual Transmission) or the Transmission Range Switch (Automatic Transmission) through the PPL (806) wire. When either the Clutch is disengaged or the Automatic Transmission is in Park or Neutral, voltage is then applied to the coil of the Starter Relay through the PPL (1035) wire. Since the Starter Relay is permanently grounded at G105 through the BLK (150) wire, the relay will energize.

Voltage is applied at all times to the Starter Relay contacts from Fuse 6 through the RED (242) wire. When the Relay energizes, the relay contacts close, and voltage is then applied to the Starter Solenoid. Since the Starter Solenoid is permanently case grounded, the Solenoid will energize two coils. The Pull-in Winding coil will energize to pull the Starter Solenoid contacts closed. When the contacts close, a plunger on the contacts will cause the Pull-in Winding coil circuit to open. Then the Hold-in Winding coil will hold the Starter Solenoid contacts closed. Voltage is then applied to the Starter Motor from the Battery through the BLK (1) wire and closed contacts of the Starter Solenoid. Since the Starter Motor is also permanently case grounded, the motor will run until the Ignition Switch is moved out of Start position. When this happens, a spring in the Starter Solenoid will move the Starter Solenoid contacts and the plunger back to the rest position.

Starting and Charging Circuit Charging Operation

The generator provides voltage to operate the vehicle's electrical system and to charge the Battery. A magnetic field is created when current flows through the Rotor windings. This field rotates as the Rotor is rotated by the engine, creating an AC voltage in the Stator windings. The AC voltage is then converted to a DC voltage by a rectifier bridge. This DC voltage is then supplied to the vehicle's electrical system at the Battery terminal.

The amount of output voltage is controlled by the current supplied to the Rotor. The Regulator in the Generator uses digital techniques to control the current supplied to the Rotor. The Rotor current is a series of electrical pulses supplied by the Regulator. When the Ignition Switch is first placed in the Run position, the pulse width is very narrow. This causes the Rotor to produce a weak magnetic field. This will produce a lower output voltage to the vehicle's electrical system. Once the engine is running, the Regulator monitors the output voltage through an internal wire and changes the pulse width accordingly.

The Regulator in the Generator also controls the BAT Indicator located in the Instrument Cluster. Voltage is applied to the Instrument Cluster when the Ignition Switch is either in the Run or Start position from the GAUGES fuse through the PNK (39) wire. When the Regulator monitors that either a voltage high or voltage low condition exists with the Engine running, a ground path to the BAT Indicator will be provided through the BRN (25) wire.

On vehicle's equipped with diesel engines, the tachometer input to the Instrument Cluster is provided by the Generator. The Generator produces voltage pulses proportional to engine speed to the Instrument Cluster through the WHT (121) wire.