5.1 Charging System TroubleshootingCharging system trouble is indicated by an illuminated alternator warning light on the instrument panel, or by an under-or overcharged battery. The alternator generates electrical current by electrical induction. That is, a magnetic field is placed in motion to induce a current in a stationary coil. When the engine is running and the alternator is spinning, part of the current it produces is used to energize its electromagnetic field. When starting, some other current must be provided to initially energize the field and begin the current generating process. This current is provided by the battery. The battery current to the alternator rotor is routed through the alternator warning light in the instrument cluster. As soon as the alternator's output equals the battery's voltage, the light goes out. Normally, the warning light should be off when the ignition is off and the engine is stopped. The light should only come on when the ignition is turned on (current to the rotor) and go out again when the engine is started and the battery is being charged. Table f describes symptoms of trouble indicated by the warning light, lists tests and probable causes for the problem, and suggests corrective actions. The bold numbers in the corrective action column refer to the numbered headings in this section where the suggested repairs can be found. Table f. Alternator Warning Light Troubleshooting
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An undercharged battery is usually associated with starting trouble. Again, make sure that the battery is in good condition and capable of accepting a full charge before blaming the charging system. Causes of an under-charged battery are: the simultaneous use of many electrical accessories for long periods of time, leaving accessories or lights in operation with the engine stopped, frequent long periods of starter usage, and frequent short-trip driving. Broken or frayed charging system wiring or corroded connections at the D+ and B+ terminals of the alternator, as well as worn, corroded, or loose battery cable connections will also prevent adequate charging or increase charging time. |
