Generator & Regulator: Diagnosis Volvo V70 I

TROUBLE SHOOTING

Note. See TROUBLE SHOOTING - BASIC PROCEDURES article in the GENERAL INFORMATION section.

WIRING CONTINUITY TEST

1. Connect a voltmeter between generator B+ terminal and ground. Voltmeter should indicate battery voltage. If battery voltage is not indicated, check wiring between generator and battery.
2. Turn ignition on and ensure generator indicator light comes on. If light does not come on, check wiring between generator and warning light.

VOLTAGE DROP TEST - POSITIVE SIDE

1. Connect a voltmeter between positive battery terminal and generator B+ terminal. Start engine and run at 2000 RPM. Turn on headlights, rear window defogger and heater blower.
2. If voltage drop is more than .2 volt, check circuit between generator B+ terminal and starter for corroded or loose connections. Also, check circuit between starter and positive battery terminal.

VOLTAGE DROP TEST - GROUND SIDE

1. Connect a voltmeter between negative battery terminal and generator housing. Start engine, and run it at 2000 RPM. Turn on headlights, rear window defogger and heater blower.
2. If voltage drop is more than .2 volt, check battery terminals, chassis grounds and engine grounds for corroded or loose connections.

OUTPUT TEST

1. Ensure connections at battery, generator, and starter are clean and tight. Ensure generator, engine and body are properly grounded. Ensure generator drive belt is tight and in good condition.
2. Connect ammeter following manufacturer's instructions. Connect voltmeter leads to battery terminals. Run engine to 2000 RPM. Adjust carbon pile on tester until voltmeter reads 12 volts. Generator output should be 49-55 amps (55-amp generator), 63-75 amps (75-amp generator), 71-80 amps (80-amp generator), 81-120 amps (120-amp generator). If generator output is low, replace generator.