Alternator Output Test

Turn ignition off and disconnect negative battery cable. Disconnect alternator output wire from "B" terminal. Connect an ammeter between "B" terminal and disconnected output wire. Connect voltmeter positive lead to alternator "B" terminal and negative lead to ground. Install a tachometer and connect negative battery cable.
Ensure voltmeter indicates battery voltage. If voltmeter reads zero volt, an open circuit is present in wire between alternator "B" terminal and battery negative terminal. Check grounds and fusible link.
Turn headlights on and start engine. Set headlights at high beam and heater switch on high. Quickly increase engine speed to 2500 RPM. and check alternator output current shown on ammeter. Ensure minimum output is within specifications. See ALTERNATOR OUTPUT SPECIFICATIONS table.

ALTERNATOR OUTPUT SPECIFICATIONS