How To Test Alternator Output Amps. Look at the display on the multimeter. Check that the alternator is actually turning.
The control side which is usually composed of multiple small wires wrapped up in electrical tape coming from the engine harness and the bigger wire going directly to the positive post of the battery. Any easy way to test the output in amps of the alternator. Clamp the amperage meter around the BAT wire leading from the alternator to the battery.
The very first thing you need is to measure the voltage output of your cars battery.
If these checks do not reveal a fault disconnect the battery earth terminal and check the alternator leads with a voltmeter. If your amperage is too low then you probably need a new alternator source. Let the engine idle at around 1200 rpm. Check your cars manual or parts manual to see what your alternators maximum amperage should be.
