What does the alternator do?
The alternator is a vehicle’s electrical power plant. Once the battery provides the power to start the car, the alternator uses the rotational movement provided by a pulley and a serpentine belt to turn a series of magnets and copper windings to produce AC electricity. This AC current is rectified (converted) by a set of diodes inside the alternator to the DC power needed for the spark plugs, electric fans, lights, etc. This electricity is also used to recharge the battery.
What are the symptoms of a faulty alternator?
The dreaded red battery light, and more importantly, no electricity to power the car. The battery in a vehicle is only meant to start the car, not to power any of the electronics. It will provide power for a short while when the alternator conks out, but once it is discharged or depleted, then the car will stall and not restart.
What is the severity of a faulty alternator?
Critical. The red battery light should be warning to get the car to the shop as fast as possible, or else we will be calling the tow truck. The replacement of the alternator is a common repair, and will be provided by most shops. Most alternators will be replaced within the day, however plan on dropping the car off early and picking it up near the end of the day.
Price for replacement will usually come down to make and model with higher prices belonging to cars that consume more electricity - Cadillac, BMW, Mercedes. Alternators will range in price from $250 to $600. The serpentine belt that turns the alternator should be changed at this time if the belt is old and worn because there will be no extra installation in the price. The belt will cost about $40 to $70. Installation will depend on where the alternator is located on the belt system, and how many other parts need to be taken off for access. These prices can range from $85 to $300.
Again, pricing will vary by location and your vehicle make and model. Save time by using Openbay to compare and book an appointment with a service center in your area.
Service article written by an ASE Master Technician