What would cause an alternator to overcharge?
Improperly jump-starting the vehicle can send a surge through the battery that destroys one or more cells in the battery or shorts it out. This surge disrupts the wiring in the alternator, causing an overcharging condition.
Can an alternator test good and still be bad?
The only way to know if an alternator is good or bad is to bench test it on an alternator test stand. Charging output can be tested on a vehicle with a digital voltmeter. If an alternator can produce normal voltage and current during a bench test, the problem is not the alternator but something else on the vehicle.
What does it mean when your alternator is not charging?
If the voltage is still only 12.4-12.6 once the engine is running, then the charging system is not functioning. In most cases and in most vehicles, you will have a battery light illuminated that indicates that the alternator is not charging.
Where can I go to test my alternator and charging system?
If any testing or replacement of your alternator or charging system becomes too difficult of a job, consider visiting one of our Preferred Repair Shops in your area can help you diagnose and repair any faults in the charging system.
Why do I have to replace my alternator and starter?
Alternator and Starter Diagnosis. Rotating electrical parts such as starters and alternators often have to be replaced on older, high-mileage vehicles. Fuel injection has helped prolong the service life of starters by allowing engines to start more quickly when they are cranked. Such is not the case with alternators.
What’s the battery voltage on an old alternator?
The old alternator tested good at Autozone. The battery has 11.8 volts now. Turning on the ignition drops that to 11.6. Starting the car drops it to 11.4. The alternator to body voltage with the engine running is 11.4 volts.