How to test voltmeter leads?
1. Turn on the power switch of the multimeter, turn the knob on the multimeter to the diode (beep) position, and insert the red and black test leads into the correct position of the multimeter.
2. Short-circuit the red and black test pens to hear a beeping sound, and the red led light on the multimeter is on to ensure that the multimeter is available.
3. Touch the red and black test leads to both ends of the circuit to be measured. If you hear a beeping sound and the red LED light on the multimeter is on, the circuit is connected; if there is no beeping sound and the red LED light on the multimeter is off, the circuit is broken.