If you are wondering if you need to replace your alternator first see if your car has any power. If not this could mean the battery or your alternator is dead.
Your alternator serves as the power plant that provides your car’s electrical supply. Whereas, your battery serves to store it and provide your alternator with the charge to get it started again.
How an Alternator Works
Your alternator is connected through belts to your engines crankshaft. As your engine turns, the rotor’s positively and negatively charged magnetic fields are exposed to three coils of wire in sequence. As each field crosses over, it creates an electric current that changes direction each time the rotor turns.
This is the alternating current the term alternator is referring to. The car’s diodes convert the altering current to direct current for the battery as well as the other parts of the car.
The need for a magnetic field from the rotor to produce power generally means the alternator requires a starting current just to begin producing power. This means it will require a battery connection to start with, otherwise no power will be produced even if the car is turning the rotor.
What You Will Need to Replace an Alternator
You will need a few tools as well as safety gear to replace your alternator as well as a replacement alternator. Here is a list.
- wrenches as well as ratchet and socket set
- gloves & goggles
- belt tensioner
- memory saver (Only necessary for some cars, mostly modern ones.)
How to Replace an Alternator
There are too many car designs to cover all possible variants in alternator hookup and design. However, we will give a generic procedure. This should give you a good idea how to replace an alternator for most models.
We cannot guarantee that your car will be compatible with these procedures. So, it is always wise to consult your vehicle specific manual before working on your car.
Here is an idea on how to replace most automotive alternators.
- Disconnect the negative battery terminal. This is absolutely critical! The alternator possesses some always hot wires that could shock you. However, before disconnecting, check if you need to attach a memory saver for your model.
- Find your alternator. Depending on your engine, this could be located anywhere on the front of your engine. Look for a roughly coconut sized unit connected to your belt system. It will have many vent holes and likely you will be able to see the coils of wires inside the unit.
- Jack up the car if necessary. If the alternator is only easily accessible from underneath the car, jack it up. Afterwards, place jack stands securely before you ever get underneath the vehicle.
- Release belt tension. The way to do this varies heavily depending on the model. This may use a tensioner unit you will need to operate to release tension. It may simply use one of the components manually belted in place such as the alternator. If so, look for one of the components bolted along a rail.
- Remove the belt. Before removing the belt, make sure you know how it will go back on. The belt routing diagram is often posted somewhere in the engine compartment. If you cannot locate it, take pictures to remind you of how it is routed.
- Disconnect the electrical connectors. Make sure you disconnect the negative battery terminal. Then, securely set it aside where there is no chance of it coming in contact with the battery terminals. It is a good idea to cover it with an insulated material as well as setting it out of the way. If you do not have an electrical diagram, take photos.
- Inspect the electrical connectors. Make sure there are no breaks in any of the wires. Also, look for corruption in the wire connectors as well as the alternator itself. If there is a significant amount, try and diagnose the cause before installing the new alternator.
- Unbolt the alternator. This isn’t too difficult, just find the bolts connecting it to the engine and remove them. Be careful not to drop it when you are removing the last bolt.
- Inspect the battery. Before you install your new alternator inspect your battery. Make sure it does not have excessive corrosion or buildup on the terminals. If it is suffering from any of these or if it is more than a year old, consider taking it to an auto parts store for testing. A poorly functioning battery could damage your new alternator.
- Replace the alternator. Make sure it will work with your model and reverse the steps of removal. Make sure nothing bridges any electrical wires and that you securely connect everything before you reconnect the negative battery terminal.
Diagnosing a Malfunctioning Alternator
A malfunctioning alternator will leave several warning signs when it begins to malfunction. Here are a few to look out for.
- Dead Battery: If your alternator dies altogether, the easiest way to tell will be when the battery dies. If your battery fails and you did not leave anything on with the car off, there are two primary reasons that could cause it: a bad alternator or a bad battery.
- Poorly functioning parts: If your headlights are dim or flickering or your other lights are suffering from the same thing, this could mean the alternator is becoming weak. A poorly working window or windshield wipers could mean the same thing as well.
- Warning lights: The final and possibly first way you can tell is the alternator or battery warning lights. Depending on your vehicle, you may have an alternator light separate from a battery one. Otherwise, a battery warning light may just indicate a general problem in your electrical system, including the alternator.
Related Questions
How Far Can I Drive with a Bad Alternator?
This really depends on how old your car is. A newer car should be able to drive a bit over twenty miles. But, an older car should be able to drive farther, since they are less dependent on the battery to keep running.