How to Diagnose Alternator Failure
The alternator in a car is the device that produces and manages most of the electrical current running throughout the vehicle. Failure of the alternator can result in problems varying from slight inconveniences to serious hazards. If you suspect alternator failure you should try to diagnose the problem immediately in order to perform the needed repairs.
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Instructions
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Start your engine and make sure the alternator light on the dashboard lights up briefly before going dim. The light will not come on if the alternator is faulty.
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Turn on your air conditioning to determine whether the power overloads the alternator. If your engine stills runs with the air conditioning on, turn on your headlights.
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3
Drive your vehicle and monitor the performance of its engine while driving at regular or highway speeds. Frequent slips of the drive belt or full-out cuts in power can indicate a failing alternator.
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4
Listen for grinding or crushing noises in your engine while it is running. This can be from the alternator. Spin the alternator by hand and listen for the noise again.
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Turn off the engine and any other features such as the radio and heat. Connect the red wire of the voltmeter to the positive terminal on your battery and attach the black to the negative terminal. Make sure the display is set to read in DC.
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Start your car up and press the gas to rev the engine. Read the display on the meter. Any reading lower than 12 volts means your alternator is failing.
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Tips & Warnings
Have your local mechanic bench test your alternator to see if it is performing at less than full capacity.
Do not attempt to drive using a damaged or improperly installed alternator, as this can be dangerous and lead to engine failure.
Always make sure your engine is completely cool before working on it.
References
- Photo Credit Creatas Images/Creatas/Getty Images
