Nippondenso Alternator Units

1. Connect Sun Vat 40, or equivalent, to vehicle. Turn selector switch to position No. 1 (starting).
2. Start engine and let idle until it reaches normal operating temperature.
3. Raise engine speed to 2000 RPM and hold it there. Read voltage on charging system tester. If voltage is over 15.1 volts, replace voltage regulator. If voltage is not over 15.1 volts, continue test.
4. Allow engine to idle. Ensure all accessories are turned off, then turn selector switch to No. 2 position.
5. Disconnect inductive pick-up from battery and zero ammeter, then place inductive pick-up over battery ground cable, with arrow pointing away from battery.
6. Raise engine speed to 2000 RPM and hold it there. Read voltage on charging system tester. If voltage is less than 13.9 volts, test battery. If voltage is not over 13.9 volts, continue test.
7. Apply load with charging system tester until voltage reads between 12 and 13.5 volts. If amperage is 55 amps or more, charging system is OK. If amperage is below specified amount, continue test.

Fig. 2 Alternator Full Field Access Hole Location:

8. With engine speed still at 2000 RPM, ground full field access hole in rear of alternator and note amperage reading, Fig. 2. The voltage will rise quickly when alternator is fully fielded. Do not allow voltage to exceed 18 volts or damage to electrical system may result.
9. If amperage reading during full field operation is less than 55 amps, test and repair alternator. If amperage reading is specified amount or more, continue test.
10. Turn engine off, then turn ignition switch to On position and disconnect 4-P connector from alternator.
11. Check for voltage at IG (black/yellow wire) terminal of 4-P connector. If battery voltage is not present, repair open in black/yellow wire. If battery voltage is present, replace voltage regulator.