How Does a Mechanic Check a Car Alternator's Volt Output?

Schedule Brake Pad Replacement
Service Area

$124.62 - $450.29

Price range for all vehicles
Average rating from 10,920 customers who received a Brake Pads Replacement.

Have you ever wondered how a mechanic checks your alternator? It’s not something that has to be done all that often, because usually alternators are maintenance-free, and they can last for up to 12 years without needing repairs. When they fail, though, they have to be fixed or replaced, because your car can’t run on battery power alone – once the charge is gone, your car stops running.

It’s a good idea to have a mechanic test the alternator from time to time, especially if you’re seeing your “charge” icon come on and stay on when you start your car. This doesn’t necessarily mean you have a bad alternator, although it’s definitely an indication that something is wrong, so have a mechanic test your alternator.

How mechanics test the alternator

Mechanics uses a computerized charging system tester to check your alternator. This is called an AVR test, and it can show if there’s a weakness in the charging system, or if you’ll need to repair or replace your alternator. It can also identify problems like blown fuses, faulty wiring, a defective ignition switch, a loose drive belt, or other issues.

A mechanic could also perform a voltage test, which is designed to measure voltage in your battery with the engine running, and with it off. Voltage should increase when the engine is started, since the alternator delivers additional power. If it doesn’t increase, then there’s a charging system problem.

A bad alternator is usually due to one or more common problems. Sometimes, the contact rings or the carbon brushes become worn. Bearings can go bad (this could be the case if you’re hearing a whining noise from your alternator), or the voltage regulator could be damaged. Sometimes, it’s possible to repair your alternator. Other times, replacement is the only sensible solution. YourMechanic can help you identify alternator problems before they become severe.


Next Step

Schedule Brake Pad Replacement

The most popular service booked by readers of this article is Brake Pad Replacement. 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 10k 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 Brake Pad Replacement reviews

Excellent Rating


YourMechanic Brake Pad Replacement Service

Average Rating

4.9/5

Number of Reviews

10,920

Rating Summary
10,410
326
67
33
84
10,410
326
67
33
84

Bernie

50 years of experience
41 reviews
Bernie
50 years of experience
Honda Accord - Brake Pads Replacement (Rear) - Phoenixville, Pennsylvania
I specifically asked for Bernie to come back, since I was so pleased with the work he did on our other car. This time I got to meet Bernie personally. He is a kind family-man who exhibited the quiet confidence of someone you would expect with the 50 years of automotive experience that he has. I felt very comfortable giving him the key to my car. Two of my kids (ages two and four) came out to greet him, since they remembered him from his first visit. Bernie is great around kids and was very kind to my two-year old son who was trying to "help" Bernie do his job. Thanks again, Bernie!
Honda Odyssey - Brake Pads Replacement (Front, Rear) - Phoenixville, Pennsylvania
I was very pleased with Bernie's work, professionalism, and courteousness. Best brake job I have ever had, and I have had many done (and several done myself, but not on this vehicle). This was a maintenance appointment -- not a repair of something broken -- so I was surprised when the brakes felt so much better after Bernie did the work. You can really see the care he took with our vehicle when I examined everything after he was finished. Thanks, Bernie!

Daniel

9 years of experience
17 reviews
Daniel
9 years of experience
Hyundai Sonata - Brake Pads Replacement (Front, Rear) - Sacramento, California
Awesome customer service. On time and answered my questions with patience. Listened to my concerns and made helpful suggestions. Seemed very knowledgeable and experienced. I will be glad to request him again. Thank you!!

Breck

18 years of experience
532 reviews
Breck
18 years of experience
Toyota RAV4 - Brake Pads Replacement (Rear) - Conroe, Texas
Breck was awesome! He called ahead of time and asked if he could arrive early. He was friendly and easy to talk to. He made me feel comfortable with the service he was going to provide and explained things clearly to me. He smiled and made this experience a good one. I will absolutely be booking future appointments with Breck and I will recommend him and Your Mechanic services to others I know. Thank you!

Brian

19 years of experience
101 reviews
Brian
19 years of experience
BMW Z4 - Brake Pads Replacement (Rear) - Phoenix, Arizona
Brian knows what he is doing and I am so happy yourmechanic.com suggested him for my Z4 car inspection prior to purchasing and even happier he was available to perform my 1st service on the vehicle I purchased. His knowledge on the brand gave him ability to to an in depth inspection and he communicated very well informing me what to prepare for in ownership of my BMW. When he came to perform maintenance on my vehicle he shared so many tips with me. I will absolutely be having Brian come back out when I need future servicing on my car.

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