How do you test car altinator?

Answer 1

Get a digital multimeter or a test light which has a voltmeter on it (if you can find one... mine was made by Snap-On, and probably cost more than you want to spend on a tool). Set it to measure volts, and, with the vehicle running, put the black lead to a good ground, and put the red lead to the stud which protrudes from the back of the alternator - the wire to the battery positive will be attached to this stud. You should be reading in the vicinity of 14 volts - no more, no less.