Alternator and Regulator Circuit Troubleshooting

Alternator and Regulator Circuit Troubleshooting

Special Tools Required

- Alternator, Regulator, Battery & Starter tester OTC3131

1. Make sure the battery connections are good and the battery is sufficiently charged.

2. Connect the alternator, regulator, battery & starter tester (OTC3131) to the battery as shown.






3. Start the engine. Hold the engine speed at 3,000 rpm with no load (in N or P) until the radiator fan comes on, then let it idle.

4. Do the charging system test.

5. Raise the engine speed to 2,000 rpm, and hold it there.

Is the voltage within 13.5-15.1 V?
YES - Go to step 6.

NO - Based on the following symptoms, take the appropriate action:

- If the voltage less than 13.5 V, go to alternator control circuit troubleshooting. Alternator Control Circuit Troubleshooting

- If the voltage over 15.1 V, go to replace the alternator Removal and Replacement or rear housing assembly. Overhaul



6. Check the alternator, regulator, battery & starter tester display.

Is the amperage 87.5 A or more?
YES - The charging system is OK.
NOTE: If the charging system indicator is still on, replace the alternator. Removal and Replacement

NO - Replace the alternator Removal and Replacement or repair the alternator. Overhaul