What is the alternator light?

• A. The fuel gauge
• B. The temperature warning light
• C. The alternator light
• D. The airbag indicator

Answer: (C)

The light is a warning about the vehicle’s charging system. The alternator’s job is to charge the battery while the engine runs, so if this light comes on, it signals that the alternator isn’t producing enough electrical power or there’s a fault in the charging circuit (like a slipping belt, bad wiring, or a failing alternator). That means the battery may not stay charged and the car could stall if you continue driving.

Fuel gauge, temperature warning light, and the airbag indicator each serve entirely different purposes—fuel level, engine overheating, and airbag system status, respectively—so they aren’t describing the charging system.

If this light appears while you’re driving, it’s wise to have the charging system checked soon, since a failing alternator can leave you with a dead battery.