Start the engine and connect a volt meter set on 20 Volts DC to the battery posts. Red probe to positive and black to negative. You should get a reading of from 13.5 to 16 volts. Any less or more and the alternator is defective.
Change alternator or check alternator brushes
The easiest of all ways to check if your alternator is working is. Turn your car on and disconnect the negative battery cable. If your car dies your alternator is no good. But if it stays on. the alternator is generating power. its basically your cars power plant.
inside the alternator. check the fusable link at the alternator and at the starter before changing the alternator.
Is the battery dead? Check for 12v on the main alternator cable. If no power, check for burned out fusible links between alternator and battery. You may need a wiring diagram to check further.
Check fuseable link on alternator Check fuseable link on alternator
the alternator belt could be slipping so check the belt, the wiring at the alternator could be faulty do a check with a multimeter. open the alternator and check the diodes .apply battery power and see if the rotor still spins inside the stator see current output
To check if your alternator is working properly, the easiest way to get it checked is to take it to a Kragens or Autozone, They will checkj it for free.
Simple, have the alternator checked and if it is okay, check the alternator circuit to the battery
usualy if the alternator is not defective then its the battery. you should start by cleaning the battery post. then you could check the terminal wire that runs from the battery post to the alternator. if thats not it you should check the ground on the alternator.
You don't. Disconnecting a battery cable to "check" the alternator is not a good idea. The removal of a cable with the engine running cuases a voltage spike that can damage the computer system on the car. The proper way to check the alternator is with a volt meter.
How to Tell If Your Car Alternator Is Bad Check related link below…
How to Change an Alternator: Video Series check related link below