In addition to voltage, what should be monitored to confirm an alternator is charging?

• A. RPM gauge.
• B. Ammeter.
• C. Oil pressure.
• D. Engine coolant temperature.

Answer: (B)

Monitoring the current delivered by the charging system is essential, because voltage alone only shows potential to charge. The ammeter indicates the actual amperage flowing into the battery and electrical system. When the engine is running and the alternator is charging, the ammeter should show positive charging current. If it’s low, zero, or negative, the alternator isn’t delivering charge even if the voltage reads normal. The other gauges—RPM, oil pressure, and engine coolant temperature—relate to engine speed or health, not to the charging process.