Alternator In-Vehicle Testing

Disconnect battery and alternator before arc welding on vehicle.




The alternator can be checked on the vehicle using a voltmeter. Connect a voltmeter across the battery ( + ) and ( - ) terminals.
1. At idle, the voltmeter should read approximately 14 volts.
2. On acceleration at 2,000 RPM, the voltmeter should read approximately 15 volts at no load.
3. At 2,000 RPM, turn on the headlights, heater, rear window defogger, and windshield wipers. The voltmeter should read approximately 13 to 14 volts.