Before diagnosing starter problems, ensure that the battery is fully charged. If the starter motor does not turn when the switch is operated, check that the shift lever is in Neutral or Park (automatic transmission) or that the clutch pedal is depressed (manual transmission). Additionally, make sure the battery is charged and all cables are clean and secure. If the starter motor spins but the engine does not crank, the overrunning clutch in the starter motor may be slipping and the starter motor will need to be replaced. If the solenoid clicks but the starter motor does not operate, the issue may lie with the battery, main solenoid contacts, starter motor, or a seized engine. Check the starter relay if a short circuit or power failure is suspected. If the solenoid plunger cannot be heard when the switch is actuated, it could indicate a bad battery, burned fusible link, or defective solenoid. To check the solenoid, connect a jumper lead between the battery (+) and the ignition switch terminal on the solenoid. If the starter motor operates, the solenoid is fine and the problem lies elsewhere. If the starter motor still does not operate, remove the starter/solenoid assembly for further testing and repair. If the starter motor cranks the engine at a slow speed, ensure the battery is charged and all terminal connections are tight. Partial engine seizure or incorrect oil viscosity can also cause slow cranking. To test the starter motor, run the engine until normal operating temperature is reached, then disconnect the coil wire from the distributor cap and ground it on the engine. Connect a voltmeter to the battery and crank the engine, taking voltage readings. A reading of nine volts or more at normal cranking speed is normal, indicating a faulty motor if the cranking speed is slow. If the reading is less than nine volts and the cranking speed is slow, the solenoid contacts may be burned, the starter motor could be bad, the battery may be discharged, or there could be a bad connection.