A multimeter can test for continuity, which shows if an electrical signal is successfully traversing the circuit. ... Running a diode test will indicate whether or not the diodes are working.

To test it, set the multimeter to measure voltage. Insert a probe into each slot and read the line voltage measurement. A properly working outlet gives a reading of 110 to 120 volts.

The Innova 3340 Professional Automotive Digital Multimeter is a high-end device that is specifically designed to pinpoint engine issues, test alternator diode, wiring, breaker points and many ...