The alternator takes energy generated from your engine and turns it into electricity that recharges your battery as you drive around. If the battery drains while you are driving, this typically means the alternator is going bad and needs to be replaced. You can tell the battery is draining by a weakening signal on the car radio and your headlights getting dull as you drive. Here is how you can replace an alternator with a new one you found at a used auto parts store.
Step One: Disconnect the Battery
Take the positive and negative cables off of the battery. Removing the battery cables protects you from getting shocked with electricity while working.
Step Two: Remove Old Alternator
The wires coming from the engine and battery connect to the alternator using electrical harnesses. Press down on the tabs on the harnesses to release and separate them. Set the wire harnesses aside.
The serpentine belt in the car goes around the pulley on the alternator. You need to remove this belt before you can unbolt the alternator from the engine block. There is a tension pulley along the serpentine belt that is used to keep the belt tight. You can move the tension pulley up and down by putting a long-handled wrench onto the nut in the middle of it and turning it clockwise. Slide the belt off of the alternator once the tension is loosened on the serpentine belt.
The alternator is bolted to the engine block with a bracket. There are usually anywhere from two to four bolts holding the alternator to the bracket. Loosen and remove all the bolts. You should be able to lift the alternator right out of the car at this point.
Step Three: Buy Replacement Alternator
Take the alternator to the used auto parts store with you. You want to make sure the wire and the bolt connections match up perfectly to the old alternator you took out of the car. You should also make sure the used auto parts store does a test on the replacement alternator to make sure it is working well before you buy it. You don't want to put in the effort to install a new alternator in your car only to find out it doesn't work either.
Step Four: Install New Alternator
Set the alternator in place and bolt it to the bracket. Twist the nut on the tension bolt arm to loosen the serpentine belt so you can slide it over the pulley on the new alternator. Connect the wire harnesses and battery. Start the car and run it for a little while to give the new alternator time to recharge your battery.
Contact a store like Hardys Auto Parts LLC for more information.