Turn off the circuit breakers that run the air conditioner, including the outside contactor located near the outdoor unit of a central air conditioner.
Disconnect the wires that supply power to the motor using the wire cutters and the appropriate screwdriver. Some connections use Phillips screws while others use straight-edged screws. Leave the wires that run from the capacitor to the motor connected for the time being.
Turn the volt-ohm meter to the volts position. Create the testing circuit by connecting the leads from the meter to the wires of the capacitor. Hold the leads in place until the meter reads zero.
Disconnect the wires that connect the capacitor to the motor. Switch the meter to the ohms setting. Hold the leads on these wires for a count of three while the electrical current from the meter charges the capacitor.
Reverse the position of the leads on the wires of the capacitor by switching the places of the black and red wires coming from the volt-ohm meter.
Replace the capacitor if the meter doesn't move toward infinite ohms. Failure to move toward infinite ohms indicates a bad capacitor.