Regulator Power Source Test
1. Turn ignition switch to the ON position, but do not start engine.2. Disconnect 2-terminal multi-plug at rear of alternator and connect positive lead of a suitable voltmeter to metal "S" terminal in disconnected wiring harness. Connect negative lead of voltmeter to a good ground.
3. Disconnect "B" terminal connector and measure voltage on "B" terminal connector.
4. If voltage is less than base voltage, repair circuit between battery and "S" or "B" terminals.
5. If voltage is base voltage or more, refer to Rotor Field Coil Test. Rotor Field Coil Test