Complete charging system explanation for Toyota Vehicle. Typical charging system components include: IGNITION SWITCH When the ignition switch is in the ON position, battery current energizes the alternator. ALTERNATOR Mechanical energy is transferred from the engine to the alternator by a grooved drive belt on a pulley arrangement. VOLTAGE REGULATOR. BATTERY The battery supplies current to energize the alternator. During charging, the battery changes electrical energy from the alternator into chemical energy. FUSING A fusible link as well as separate fuses are used to protect circuits in the charging system. TOYOTA COMPACT, HIGH-SPEED ALTERNATOR Beginning with the 1983 Camry, a compact, high-speed alternator with a built-in IC regulator is used on Toyota vehicles. Corolla models with the 4A-C engine use a different alternator with an integral IC regulator. Alternator Terminals Toyota’s high-speed alternator has the following terminals: “B”, “IG”, “S”, “U’, and “17″. Regulator While engine speeds and electrical loads change, the alternator’s output must remain even - not too much, nor too little. IGNITION ON, ENGINE STOPPED. Diagnosis and Testing The charging system requires periodic inspection and service. Specific problem symptoms, their possible cause, and the service required are listed in the chart below. Output Circuit - Insulated Side. CHARGING CIRCUIT RELAY TESTS Various charging system layouts are used on. Toyota vehicles.