Diagnosing an Alternator Problem

Series Summary

Your car is a complex machine made up of interconnected parts. One of these parts, the alternator, ensures that your battery remains charged; while the engine is running in your car the serpentine belt is continuously supplying energy to the alternator which then energizes the battery. When the alternator breaks your car will run on battery power for a very short period of time and then it will not start and work properly again until power is restored to your battery and the alternator is fixed. Changing an alternator requires many different disassembly steps and can be a daunting task even with a manual to guide you. However, there is another option: you can watch for free online as of one of our experts demonstrates how to change the alternator in a car.

In this free online video series learn how to change the alternator on your car from certified mechanic Nathan McCullough. Watch these videos and learn alternator diagnosis as well as how to disconnect the battery on your car; and how to locate the alternator; how to remove the alternator by disassembling the intake, removing the throttle linkage and radiator hose; learn how to unplug the vehicle electrical connectors from the alternator; how to remove the serpentine belt; and how to install the new alternator and alternator bolt.

Video Transcript

"Hi! My name is Nate McCullough on behalf of expertvillage.com. In this clip we are going to talk about the proper way for some test procedures to determine if your alternator has failed. There are various different tools that you can use. I myself for the cost and effectiveness like to use this simple task light. All this is is a circuit with a light bulb in it. You hook it up from power to ground or from ground to power and you can see the light bulb lights up. That indicates that the battery and its related components have good connections. This is going to test the wiring through the positive side, all the way through to ground; we've got a good connection here. Now what we are going to do is test the wiring from the battery through the alternator to make sure we don't have a failure there. We take and hook up our lead there, we are going to test this terminal here. This is our bus type fuse. There is a large fuse in here that runs through there through the wire to the alternator. That indicates that the wiring from the battery to here is good. We are going to check across the fuse. As you can see the bulb is lit up. That indicates that the fuse is good. We have one last leg of wiring to check and that is going to be back down over in this area. As you can see, that lights up. That's checked all the wiring from the battery through the alternator. If you light lights up from there all the way through there, that indicates that the wiring is good and the failure is more than likely in the alternator. As far as the alternator goes, there is not much you can do to it as far as maintenance. They are re-buildable. However getting the proper components to rebuild that alternator can be next to imposition. We checked the 4 parts stores today and couldn't come up with what they call brushes. That is the one wearing component in your alternator. They are what makes the electrical connection between the magnet and the commutator. They do wear, they are made of carbon. Like I said we couldn't find any. They have pretty much become a sealed unit and are replaced as an assembly. There are no greasable components on it. It doesn't require any lubrication. It is all factory sealed. "