Connect an Examiner in Voltmeter mode with the positive terminal to terminal D+ of the alternator and the negative earthed
With the ignition on, ensure that the measured voltage is less than 5.5 Volt and that the generator warning light on the panel is on
If the voltage is interrupted, the alternator is inefficient and should be replaced
Start the engine and check, with voltage D+ greater than 5.5 Volt, that the generator warning light on the panel goes off and a correct battery recharging indication is displayed.