Alternator/Regulator Operation Test

Alternator/Regulator Operation Test

CAUTION: Be careful during testing as the radiator and condenser fans come on suddenly while the engine is running.

Be sure to use a good battery. Connect an ammeter and a voltmeter to terminal B as shown.

NOTE: Be sure to use an ammeter capable of measuring amperages higher than 120 A

Start the engine and let it idle until it reaches normal operating temperature (radiator fan comes on two times).

Raise the engine speed to 2000 rpm and hold it there. Turn the headlights (HI) on and check the voltage at the battery terminals.

CAUTION: As the headlights warm up considerably, do not cover them

Is there voltage between 13.9 and 15V?

• NO: Test the alternator components.
• YES: Turn the blower motor and the rear window demister on, and check the battery voltage.

Is there battery voltage less than 13.5V?

• NO: Turn on the fog lights, brake lights, etc.
• YES: Read the amperage.

Are there more than 50A?

• NO: Test the alternator components.
• YES: Alternator/regulator operation is OK. Test the alternator components