Be sure the starting motor switch is in the “OFF” position to prevent electrical shock and personal injury.
Remove the wire connecting the starting motor switch to the magnetic switch (marked “S” or “START”) from the starter switch terminal.
Connect the positive (+) lead of the digital multimeter, Cummins Part Number 3164488, or equivalent to the starter switch terminal and the negative (-) lead to a chassis or engine ground location.
NOTE: Set the multimeter to indicate DC volts with the starting motor switch in the “OFF” position, there must not be voltage at the starter switch terminal. If the meter indicates voltage, the starter switch is malfunctioning and must be replaced.
If there is no voltage, turn the starting motor switch to the “OFF” position.
Connect the multimeter positive (+) lead to the starter switch terminal having a wire connecting the starter switch to the starting motor solenoid B terminal.
Turn the starting motor switch to the “START” position.
If the meter indicates system voltage at the starter switch input terminal, the starter switch is defective and must be replaced. Refer to the manufacturer’s procedure for replacement.
If the meter indicates no voltage, the switch is not the cause of the complaint.
Check the wiring from the starter switch to the starting motor solenoid B terminal and from the starting motor solenoid to the battery for broken or damaged wires.
Hello, I'm Jack, a diesel engine fan and a blogger. I write about how to fix and improve diesel engines, from cars to trucks to generators. I also review the newest models and innovations in the diesel market. If you are interested in learning more about diesel engines, check out my blog and leave your feedback.
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