How do I test my car's alternator?

Answer by  worker2211 (46)

Clean +, - battery terminals. Connect + and - clamps of tester to battery. Turn ON, choose "full charging system test. " Test result showing diode ripple problems indicates bad alternator.

Answer by  Doug77 (1433)

If you have a 12 volt test light/volt meter: Start the car with nothing on but, your tester connected to the battery. One by one, turn all of your accessories on. The tester should read a continuous 14 volts and should never drop below 12 volts. Also, listen for a high pitched hum with a heavy load - that's normal.

Answer by  Amber40 (24961)

The best place to test it is to go down to your local auto parts store and have them run a free check on it for you. You can use a multimeter to check it yourself to see it it it charging with more than 12 volts.

Answer by  Adam17 (161)

The best way is to remove the alternator and take it to be bench tested at an auto parts store. Many will perform this for free.

Answer by  Amber40 (24961)

You can either test it yourself with a multimeter or have a auto-parts store test it for you. Most place like Advance and Autozone well test your alternator for free. If you do it yourself really all you can test is the voltage output.

Answer by  kqwik (317)

Yuo happen to have a special alternator considering most cars are 12 volt. I would bring the laternator the the dealer of your vehicle and they should be able to test it for you. Otherwise see if you dash has a volatge gauge and make sure it is charging while running.

Answer by  kennethjgoodson (4903)

The best thing to do is get a volt meter from your local tool store and touch the ground to the black terminal and put the red wire on the positive side of the battery. This will show you the volts coming off the alternator to the battery.

Answer by  Amber40 (24961)

You can test the out put of the alternator with a voltage gauge or a multimeter. Just attach it to the lead on the alternator and measure the voltage at idle and under part throttle. You should see something between 12.5 to 14 volts typically.

Answer by  redmamaof5 (188)

Take it to a ahop and have them test it. They need to put a load tester on it to determine if there is enough juice going through it. If its not dying out while driving it then it is not the alternator but hte battery.

Answer by  Kumar73 (26)

You have to check carbon brushes of alternator for any wear and tear, because if there are excessive wear and tear then your alternator will not give proper output. You should also check the connections of the alternator.

Answer by  japratt (1687)

In order to test your car's alternator you will need to take it into an auto mechanic. They will be able to tell you how your alternator is being responsive.