Charging System: Testing and Inspection

1. Connect Sun VAT-40, or equivalent and turn selector switch to position 1 (starting).
2. Shift to Neutral or Park and start engine. Hold engine speed at 2000 RPM with no load until radiator fan comes on, then let engine idle.
3. Raise engine speed to 2000 RPM and hold it there. If voltage is over 15.1 volts, replace voltage regulator. If voltage is not over 15.1 volts, release accelerator pedal and let engine idle.
4. Ensure all accessories are turned Off, then turn tester selector switch to position 2 (charging).
5. Remove inductive pick-up, then zero ammeter.
6. Place inductive pick-up over battery ground cable so arrow points away from battery.
7. Raise engine speed to 2000 RPM and hold it there. If voltage is less than 13.5 volts, test and repair alternator components. If voltage is not less than 13.5 volts, continue test.
8. Apply load with tester until battery voltage drops to between 12-13.5 volts. If amperage is 65 amps or more, system is satisfactory. If amperage is less than 65 amps, full-field alternator with engine at 2000 RPM.
9. If alternator is less than 65 amps, test and repair alternator components. If alternator is 65 amps or more, turn ignition switch to Off position, then back to On position.
1O. Disconnect 4-P connector from alternator, then check for voltage at IG (black/yellow wire) terminal of 4-P connector. If there is voltage, replace voltage regulator. If there is no battery voltage, repair open in black/yellow wire.