If a malfunction occurs in the starting circuit, do not immediately assume that the starter is causing the problem. First, check that the battery cable clamps are clean and tight where they connect to the battery, and inspect the condition of the battery cables, replacing any defective ones. Test the battery's condition, and if it does not pass all tests, replace it. Check the starter solenoid wiring and connections, ensure the starter mounting bolts are tight, and confirm that the shift lever is in PARK or NEUTRAL for automatic transaxles or that the clutch pedal is pressed for manual transaxles. Verify the adjustment of the Transmission Range sensor on automatic vehicles or the installation of the Clutch Pedal Position switch on manual vehicles, and check the operation of the starter relay. If the starter does not actuate when the ignition switch is turned to the start position, check for battery voltage to the solenoid by connecting a test light or voltmeter to the starter solenoid switched terminal while an assistant turns the ignition switch. If voltage is not available, check all fuses and relays in series with the starting system. If voltage is present but the starter motor does not operate, remove the starter and bench test it. If the starter turns over slowly, check the starter cranking voltage and current draw from the battery while cranking the engine for 10 seconds or less, ensuring the voltage does not drop below 8.0 volts for manual transaxle models or 8.5 volts for automatic models, and that the current draw does not exceed 400 amps or drop below 250 amps. The battery cables might overheat due to the large current draw, so testing should be discontinued until the system cools down. If the starter motor cranking amp values are not within the correct range, replace it. Ensure the battery is in good condition, with an appropriate cold-cranking rating, and that the terminals and cables are clean and not corroded. In extreme cold, warm the battery or engine block before testing. If the starter receives voltage but does not activate, remove and check the starter/solenoid assembly on the bench, as the solenoid is likely defective. Before proceeding, try to rotate the crankshaft pulley to rule out a seized engine. With the starter/solenoid assembly mounted in a vise, connect jumper cables from the battery terminals to the starter and apply battery voltage to the solenoid S terminal for 10 seconds or less to see if the solenoid plunger, shill lever, and overrunning clutch extend and rotate the pinion drive. If the pinion drive extends but does not rotate, the solenoid is functioning but the starter motor is defective. If there is no movement but the solenoid clicks, either the solenoid or the starter motor is defective. If the solenoid plunger extends and rotates the pinion drive, the starter/solenoid assembly is working properly.
Posted by FordPartsGiant Specialist 
