Symptoms of a Bad or Failing Alternator

The electrical charging system is one of the most important systems on any vehicle. The charging system is made up of several components, including the alternator and battery, that work together to supply all of the vehicle’s electrical needs. The alternator is what specifically generates the amperage and electricity required to meet the vehicle’s electrical needs, including keeping the battery charged.

Because the alternator plays such a vital role in keeping all of the vehicle’s electrical components powered, any problems with the alternator can quickly develop into problems with another system or component on the vehicle. Usually, a defective or failing alternator will produce a few symptoms that can alert the driver of a potential issue, allowing time for the driver to service the vehicle before a bigger problem occurs.

1. Having to jump start the vehicle on a regular basis

One of the first symptoms of a bad or failing alternator is the need to jump start the vehicle on a regular basis. It is the job of the battery to provide the power to crank the engine and start the vehicle, however, it is the job of the alternator to make sure that the battery stays charged. If the alternator is beginning to have problems or has failed, it will not be able to meet the vehicle’s electrical needs, including keeping the battery fully charged. A low or uncharged battery will not be able to keep up with the load required to start an engine multiple times, and will result in a dead battery. Continuously having to jump start the vehicle may be a sign that the alternator may not be charging the battery and is therefore unable to successfully start a vehicle.

2. Dim lights

Another symptom of a potential problem with the alternator is dim or flickering lights. If you notice any sort of flickering or dimming of the lights when operating the vehicle, it may be a sign that the alternator is not generating enough power to keep up with the vehicle’s electrical needs. The dimming or flickering may coincide with certain actions when operating the vehicle, such as dimming when pressing on the gas pedal, turning up the volume on the stereo, or turning on another light. This symptom may be indicative of an alternator that is unable to keep up with the needs of the vehicle’s electrical system while it is running, and when additional loads are placed on it.

3. Battery Light comes on

One of the most common symptoms of a problem with the alternator is an illuminated Battery Light. The Battery Light will usually come on when the computer detects that the system voltage has fallen below a certain requirement. This usually means that the alternator, or perhaps one of its internal components, has failed and it is no longer able to keep up with the vehicle’s electrical requirements, and it has been detected by the computer. An illuminated Battery Light also indicates that the vehicle is now running on limited battery life. Depending on the condition of the battery, and how long the Battery Light has been on, the vehicle should be able to run for a short amount of time before the battery finally dies. At that point, the vehicle will shut off and service will be required.

The alternator is among a vehicle’s most important components, as it essentially serves to provide the electrical supply for the entire vehicle. Any problems with it can quickly translate to problems with starting and running the vehicle, which opens up the possibility of being stranded on the road. If you suspect that your vehicle may be having a problem with the alternator, or it is displaying any of the symptoms above, [have the battery and alternator carefully inspected] by a professional technician, such as one from YourMechanic. They will be able to determine if an alternator replacement is necessary, or if another issue needs to be addressed.


Next Step

Schedule Starting And Charging Inspection

The most popular service booked by readers of this article is Starting And Charging Inspection. Once the problem has been diagnosed, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. YourMechanic’s technicians bring the dealership to you by performing this job at your home or office 7-days a week between 7AM-9PM. We currently cover over 2,000 cities and have 100k+ 5-star reviews... LEARN MORE

SEE PRICING & SCHEDULING

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Recent Starting And Charging Inspection reviews

Excellent Rating

(4)

Rating Summary
4
0
0
0
0
4
0
0
0
0

Joseph

20 years of experience
640 reviews
Joseph
20 years of experience
Chevrolet Camaro L4-2.0L Turbo - Starting And Charging Inspection - Salt Lake City, Utah
Friendly, thorough , and most importantly (to me) was not dismissive or condescending. My cursory knowledge of some Chevrolet's interesting design choices with the Camaro, coupled with Joe's experience and perseverance is how we both found upon the problem. Highly recommended.
Kia Sedona - Alternator Repair - Kaysville, Utah
Arrived early, great communicator, got the job done with no pressure.

Matthew

33 years of experience
1210 reviews
Matthew
33 years of experience
Honda Accord L4-2.3L - Starting And Charging - Hampton, Virginia
Matthew was very polite and informative. I would recommend him to my friends

Anderson

27 years of experience
91 reviews
Anderson
27 years of experience
Nissan Sentra L4-1.6L - Starting And Charging Inspection - Middle Village, New York
Anderson was very friendly and professional

Greg

22 years of experience
333 reviews
Greg
22 years of experience
Infiniti G35 V6-3.5L - Starting And Charging Inspection - Tempe, Arizona
Great experience

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Related articles

How to Diagnose a Car Battery Drain
It It is safe to say that every car owner reading this has likely experienced that time where you were leaving your home or walking out to your sitting car, only to discover that the battery in your car was...
How to React If Your Battery Light is On
The battery light or charging warning light (https://www.yourmechanic.com/article/the-check-engine-light-demystified), available on the dashboard of your car, indicates malfunctioning or poor charging of the battery....
How to Replace a Car Battery Temperature Sensor
The battery has a battery temperature sensor that can fail if the Check Engine Light comes on, the battery voltage is low, or the RPM curve surges.

Related questions

Battery needs replacing.
The car won't start or the car won't turn over? Car won't start would not be the battery, but some other cause like the fuel pump or the ignition module. The battery may be the cause of won't turn over...
My car won't start
Hi there, from the symptoms you have described, it sounds more like a fuel issue. Either the fuel pump is failing and not pumping enough fuel into the engine, or some component such as a coolant temp sensor or fuel...
Window will only open, but not close
Hello there, thank you for asking about your 2003 Chrysler Intrepid. The power window motor is just a reversible DC motor, the direction of which is determined by the window switch. If the switch is OK, my guess is that...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com