How To Test Alternator Diode. SUPER EASYIn this video we will show yo uhow to test alternator diode with multimeter and find out if. The diodes are not perfect so a small amount of AC will always get out.
Measure the Base Voltage of the Battery. I have seen known bad batteries and alternators test good and vice versa. If the engine operation stops the alternator is likely to be bad.
If you are thinking that a running alternator testing may be easily done using a digital multimeter you are terribly mistaken.
You will probably see a little AC. Because the diodes are shared between the phases one defective diode causes a loss of 23 of the alternators maximum current capacity. Alternator troubleshooting with an oscilloscope is probably the only best possible way of doing it. To check for a possible bad alternator diode switch your voltmeter to a low setting on the AC alternating current voltage scale.
