See Figure 1
The starting system consists of the following components:
The starter system components comprise two separate circuits, a high amperage and a low amperage circuit. The low amperage circuit is responsible for engaging the starter's pinion drive gear to the flywheel/driveplate ring, and the high amperage circuit is the actual power supply to the starter motor upon start-up. The high amperage circuit supplies the starter with up to 300 or more amps (700 amps for diesel engine). The low amperage control circuit operates on less than 20 amps.
When the ignition switch is turned to the START position, battery voltage for automatic transmission-equipped vehicles is supplied through the low amperage control circuit to the coil battery terminal. The park/neutral position switch provides a ground path to the starter relay coil ground terminal. This way the vehicle can only be started in Neutral or Park.
For 1995-96 manual transmission models (which employ a clutch/starter interlock), the low amperage control circuit operates in a similar fashion, except that the clutch position switch supplies battery voltage to the coil battery terminal at the starter relay when the ignition key is turned to START and the clutch pedal is depressed.
If equipped with an automatic transmission, the amperage supplied to the starter relay causes the normally open relay contacts to close. The closed relay contacts then divert the electricity at the common feed terminal through the wiring harness to energize the solenoid coils. The energized coils then pull in and hold in the solenoid plunger. The solenoid plunger then pulls the starter shift lever which engages the starter overrunning clutch and pinion gear with the flywheel/drive plate ring gear.
As the plunger extends fully, the high amperage circuit is completed and current flows to the starter motor, which cranks the engine. When the engine starts the overrunning clutch in the pinion gear allows the gear to spin faster than the pinion shaft thus preventing damage to the starter from the fast-spinning engine. As the key is released from the START position to the ON position, the relay coil is de-energized and the plunger return spring pulls the plunger back to the relaxed position.
The starter motor and the starter solenoid are integrated as one unit. They are not independently serviceable. If the the starter fails, the entire unit must be replaced.