Last Updated: 05.11.2021

Your engine, entertainment, and climate system among other things are all dependent on the alternator operating properly. It’s an important component that puts the power back into the battery while you are driving.

For the alternator to effectively charge a 12-volt vehicle battery, it needs to be putting out about 13 to 14 DC volts. A reading of less than 13 volts is a warning sign that the alternator needs to be replaced.

How much does it cost to replace an alternator? That’s exactly what we want to discuss, plus, we will also go through the major signs of a failing alternator.

What Is an Alternator?

car alternator with fan belt

The alternator in your vehicle is an electrical generator that is uniquely engineered to convert mechanical energy into electrical energy. This energy is in the form of alternating current.

The electricity in the alternator is generated through electromagnetic induction. An alternator converts the AC into direct current through a system called a rectifier. The alternator’s output varies depending on the speed of your vehicle.

An alternator also uses a regulator to limit the AC to DC conversion and help maintain a near-constant output.

Symptoms of a Failing Alternator

The best way to know that you need an alternator replacement is by looking for warning signs. Here is a complete list of the most popular symptoms of a failing alternator:

Dashboard Light

dashboard warning lights battery check engine brake

When the battery in your car doesn’t get enough charge, you may see your headlights dimming than usual. This is usually accompanied by dashboard signals like the check engine light, ALT, or battery light. The ECU may fail to work properly if it doesn’t receive sufficient electricity.

Failing Electrical Systems

The power generated by the alternator is extremely important for the proper functioning of your vehicle’s electrical systems, including entertainment, headlights, heated mirrors, heated seats, stereo, power mirrors, power windows, and air conditioner.

If any of these electrical systems are failing, then you are likely to have a bad alternator. Look for any failing systems, especially when your 4WD is idle.

Failing Alternator Noises

The alternator features spinning parts, which will start to produce some unusual sounds if their movement is restricted. 

If the rotor is bad, you will hear a loud grinding noise. The noise may worsen if you’ve got worn-out bearings.

If the bearings in the alternator are excessively worn out, the alternator will smell like an electrical fire because of the excess hotness. It may even start smoking, which is a clear indication that the alternator is done for. 

A Dead Battery

A car battery will eventually die, right? But sometimes the death of the battery may be caused by a bad, malfunctioning, or failing alternator.

A failing alternator may not be charging the battery properly while the engine is on. This can lead to quick depletion of the battery. The easiest way to know if the dead battery is due to alternator malfunction is to jumpstart your vehicle.

battery with jumper cables

If you jumpstart the vehicle and it stays running, then you need a battery replacement as soon as possible. But if the battery dies again after jumpstarting, then it is a sign that your alternator isn’t pushing enough power to the battery.

Burning Rubber Smell

You are likely to experience a burning rubber smell due to the drive belt slipping on the alternator pulley. This normally causes poor voltage output. It can be due to incorrect tension or wear on the drive belt, which you can fix by restoring the ideal amount of tension to the drive belt. 

Stalling and Vehicle Not Starting

It isn’t the alternator’s job to start the vehicle, that’s the job of the battery. But if the alternator is malfunctioning and cannot charge the battery. Then the battery is likely to die. So, your vehicle will not start if the battery is dead.

If your truck or SUV is stalling most of the time while driving, then it is an indication that your spark plugs are not receiving sufficient power to keep your engine running smoothly. 

How to Test an Alternator?

Don’t be in a hurry to buy an aftermarket alternator just yet. You can do a quick and simple test to be 100% sure that the alternator is the cause of all the problems you are experiencing. 

Here are a few quick steps that will come in handy:

What You Need

  • Voltmeter

Steps to Follow

Step 1: Locate the Battery

Start by locating the battery of your vehicle, which is usually on the left side of the engine. But in some vehicles, it is on the right side. Always use your vehicle’s owner’s manual to locate the battery easily.

Step 2: Connect the Voltmeter to the Battery

Then connect your voltmeter to the battery while your vehicle’s engine is off. The red wire of the meter goes to the positive terminal of the battery and the black wire goes to a metal grounding source.

Step 3: Read the Voltage

Go ahead and read the voltage on your voltmeter. Optimum readings usually range from 13 to 14 volts, average readings range from 12 to 13 volts, and any reading below 12 volts is an invitation for a replacement.

Step 4: Turn the Engine On

Disconnect the voltmeter, turn on your engine, and then reconnect the voltmeter and switch on some of the electrical systems such as the radio. 

Take your readings, which are supposed to be higher than the ones you got initially when the engine was off. The ideal readings should be 14+ volts. Lower readings call for an alternator replacement.

How Much Does It Cost to Replace an Alternator?

Alternator Replacement Cost

Alternator replacement costs may vary from approximately $200 to approximately $700.

Having a new alternator fitted by a mechanic may cost you as little as $200 and as high as $1,000+ with an average labor plus parts cost of about $500. This, of course, depends on the make and model of your vehicle.

Alternator Repair Cost

If the alternator is not completely bad but it is malfunctioning, then you can consider repair. This is a cheaper option, considering that the cost of an alternator can be high depending on the vehicle model.

If your alternator is repairable, you should consider spending approximately $80 to $150. These figures are quite budget-friendly compared to a new alternator that can cost you a few hundred dollars.

Read also: How Much Does a Tune-Up Cost?

What If I Replaced My Alternator?

The alternator is not a very difficult system to locate in your vehicle. So, you could cut the cost of labor and only incur the cost of replacement with a DIY. 

Follow these key steps when replacing an alternator:

  • Start by disconnecting the battery
  • Loosen the belt tensioner to remove the alternator and other pulleys
  • Take a picture of the belt’s routing for proper reinstallation
  • Inspect the belt for signs of wear or glazing
  • Remove the voltage regulator connector from the back of the alternator
  • Detach the positive cable
  • Remove the nut and bolt on the alternator brace
  • Locate and remove the alternator’s lower mounting bolt
  • Lift the bad alternator out
  • Position the new alternator so you can start the lower mounting bolt
  • Replace the upper bolt and nut on the alternator brace
  • Reattach the voltage regulator connector and the positive lead to the post on the alternator
  • Route your belt over the pulleys as directed on your belt routing diagram or the photo you took
  • Raise the tensioner and loop the belt underneath
  • Ensure the belt is tight, but be careful not to overtighten the drive belt


Can I jumpstart my vehicle with a bad alternator?

Yes, a vehicle with a bad, malfunctioning, or failing alternator can be jumpstarted. If the battery is not completely dead, then it will get just enough power to get the engine started depending on how long you will leave the donor vehicle connected. The engine will run for a brief moment before the battery dies again.

What is the lifespan of an alternator?

An alternator has a considerably long lifespan of approximately six to 10 years or roughly 8,000 to 150,000 miles.

Does insurance cover the alternator?

In most cases, an alternator will die because of normal wear and tear, which is not covered by insurance. The cost of a new one is not covered as well. But if the alternator gets damaged in a car crash, it may be covered by the insurance.

Does an extended warranty cover the alternator?

Most extended warranties usually cover the alternator for mid-level coverage and higher.

Final Thoughts

How much does it cost to replace an alternator? Roughly $200 to $1000+, including parts and labor. A replacement alternator costs approximately $200 to $700. An alternator repair, on the other hand, may cost around $80 to $150. The cheapest option is an alternator repair. But when it comes to a replacement, DIY is a less expensive option since you will only incur the cost of parts. 

You might also want to know how much it costs to replace brake pads and rotors.