Alternator Troubleshooting Tips

How can I find out that my alternator is defective?

After years of service, due to the age of the vehicle, the alternator tends to wear out. One of the indicators of a faulty alternator would be the 'ALT' or 'GEN' light on your vehicle's dashboard. In addition, there are a few symptoms of a faulty alternator. The following are some of the common symptoms of a malfunctioning alternator:

Dim Lights:

A bad alternator will disturb the electric flow to the various parts of the automobile. The components powered by the alternator may either receive too less or too high voltage. One obvious symptom is the dimming or brightening of the head lights, often due to broken or loose connections in the alternator. A bad alternator will also affect the working of the dashboard lights and power windows/seats.

Unusual Sounds:

An accessory belt or serpentine belt connects the crankshaft and the alternator. A growling or whining noise is emitted if this belt loses its tension, or if the bearings or bushings are worn out. Bearing failure will also produce a squealing or howling noise.

Dead Battery:

If your battery discharges more frequently than normal, it is a symptom of a malfunctioning alternator. There may also be some problems in the electric connections that are draining the voltage out. In extreme cases, the alternator will fail to recharge the battery completely. (However, the battery can go bad even while the alternator is functioning properly. It is necessary to inspect and check which part is the actual culprit to fix the problem.)

Engine Problems:

A defective alternator induces engine problems such as rough idling, misfiring, poor acceleration and stalling. In addition, the engine may have a hard time starting, especially in cold weather conditions.


Frequently Asked Questions


Can a high-output alternator be used in standard vehicles? 

Usually, high-output alternators are used in high-performance automobiles but they can also be fit into mainstream vehicles. Find the benefits of using a high-output alternator in this link: High Output Alternator


What could be the simple way to find out whether my alternator is faulty?

Start the car (do jump starting if required) and check the output voltage of the alternator with a digital multi-meter or any other similar device that measures DC voltage. If the device reads 12 volts or less, the alternator has gone bad. If the voltage reading is within the optimal range (13.5 volts and 14.8 volts), the alternator is perfectly fine; the problem is somewhere else.


Is self-installation possible with alternators?

The installation process can be difficult or manageable depending on your automotive experience in repairing. If you are a regular DIYer, the process can be pretty manageable. The installation process also varies for different automobiles.