When to change your alternator
“The headlights will dim and other car electrics may start to malfunction - you should see a red warning light or other message on your dashboard”
Alternators can last more than 100,000 miles without an issue, especially in a car that does not have a lot of electrical accessories, like power windows, heated seats, or a high powered stereo. When the alternator stops charging (you should see a red warning light or other message on your dashboard) the battery will go flat quickly. The headlights will dim and other car electrics may start to malfunction. You probably only have a few dozen more miles before it stops running completely
When alternators stop charging it is typically a matter of burned out diodes (which convert the alternating current to direct current) or the wire windings inside can short out, resulting in a lower output than is needed to charge the battery. Even when nothing fails, the carbon brushes will wear down until they just no longer make contact. As with anything that spins, there is also a chance the bearings inside can wear out or get play in them, causing it to make noise for a while before failing completely.
All cars are slightly different, so if it is time to change your alternator, use our before you begin checklist, and find your car for specific instructions.