Alternator Output Test

Turn ignition switch to "OFF" position. Disconnect negative battery cable. Disconnect alternator output wire from "B" terminal. Connect an ammeter between "B" terminal and disconnected output wire. Connect a voltmeter between "B" terminal and ground. Connect positive voltmeter lead wire to alternator "B" terminal and negative wire to ground. Install an engine tachometer (if necessary) and reinstall battery ground cable open.
Ensure voltmeter indicates battery voltage. If voltmeter reads zero volts, 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 and shown on ammeter. Ensure minimum output is within specification. See ALTERNATOR OUTPUT SPECIFICATION table.

ALTERNATOR OUTPUT SPECIFICATIONS