A car's alternator charges the battery as the engine runs. This helps ensure you always have enough power for starting the engine and running electrical components. If yours starts to show signs of trouble, it's time to consider a replacement. Unlike an AC service where you might need to invest in an AC vacuum pump rental, you can replace a car's alternator will just a few basic tools you probably have on hand.

Diagnosis, Labor & Parts Costs

Diagnosing a bad alternator is pretty straightforward. If you notice these signs, it's time to take your car in to have the alternator checked:

• A dead battery that won't stay charged even after a jump
• Illuminated battery warning light on your dash
• A smell of burning rubber
• Dim or too-bright headlights
• Malfunctioning electronics

Once diagnosed, you can get an idea of the cost of repairs. The prices for new alternators vary, but you can expect to pay somewhere between $150 and $500 for a new one. You can save by using an AutoZone promo code. You'll also have to figure in the cost of about two hours of labor for a shop to swap it out. One final thing to note is that it's usually a good idea to replace your drive belt at the same time since it needs to be removed to take out the old alternator.

DIY vs. Professional Installation

DIY Pros and Cons

You can save a significant sum of money by replacing your own alternator. That's a huge pro in its favor. However, you can also do some serious damage if you mess up the repair. Before you take an alternator replacement on, be sure you understand the process and are comfortable executing it.

Another thing to consider is what type of part you want to use. If you want to use a used or rebuilt alternator, you may have no choice but to do the job yourself. Some shops won't work with used parts because they can't back them up. A DIY replacement also gives you more flexibility to shop around for a specific brand.

• Pros: lower cost, flexibility in part selection (new vs. used, brand, etc.), and convenience of not going to a shop
• Cons: Investment of time (approximately two to 3 hours) and possibility of damaging the engine

Professional Pros and Cons

When you take a car to a certified repair shop, you can feel relatively confident the job will be done correctly the first time. If it isn't, you can get the shop to make things right after the fact. That's a big pro in favor of a repair shop. However, that peace of mind will cost you a couple of hours of labor. You also may have to wait several days or weeks to get an appointment at a repair facility.

• Pros: Peace of mind and recourse if something goes wrong
• Cons: Higher cost and potential wait

The Parts You Need for DIY Alternator Replacement

Replacing an alternator is a relatively straightforward repair. When you decide to take it on, shop for the correct parts either online or at your local auto parts store. There, you can pick up a new alternator, drive belt, and any other tools you need to get the job done right.