Starter Motor: Testing and Inspection

DIAGNOSIS AND TESTING - STARTER MOTOR

Correct starter motor operation can be confirmed by performing the following free running bench test. This test can only be performed with the starter motor removed from the vehicle. Refer to Starting System in the Specifications for the starter motor specifications. [1][2]Mechanical Specifications.

1. Remove the starter motor from the vehicle. Refer to Starter Motor Removal and Installation for the procedures. Starter Motor - Removal and Starter Motor - Installation.
2. Mount the starter motor securely in a soft-jawed bench vise. The vise jaws should be clamped on the mounting flange of the starter motor. Never clamp on the starter motor by the field frame.
3. Connect a suitable volt-ampere tester and a 12-volt battery to the starter motor in series, and set the ammeter to the 100 ampere scale. See the instructions provided by the manufacturer of the volt-ampere tester being used.
4. Install a jumper wire from the solenoid terminal to the solenoid battery terminal. The starter motor should operate. If the starter motor fails to operate, replace the faulty starter motor assembly.
5. Adjust the carbon pile load of the tester to obtain the free running test voltage. Refer to Starting System Specifications for the starter motor free running test voltage specifications. [1][2]Mechanical Specifications.
6. Note the reading on the ammeter and compare this reading to the free running test maximum amperage draw. Refer to Starting System Specifications for the starter motor free running test maximum amperage draw specifications. [1][2]Mechanical Specifications.
7. If the ammeter reading exceeds the maximum amperage draw specification, replace the faulty starter motor assembly.
STARTER SOLENOID

This test can only be performed with the starter motor removed from the vehicle.

1. Remove the starter motor from the vehicle. Starter Motor - Removal.
2. Disconnect the wire from the solenoid field coil terminal.




3. Check the solenoid (1) for continuity between the solenoid terminal (2) and the solenoid field coil terminal (4) with a continuity tester (3). There should be continuity. If OK, go to Step 4. If not OK, replace the faulty starter motor assembly.




4. Using a continuity tester (3), check for continuity between the solenoid terminal (2) and the solenoid case (1). There should be continuity. If not OK, replace the faulty starter motor assembly.