With engine off, remove the rubber cap out of the spark plug. Start the engine and touch the tip of screwdriver to the head of the spark plug or spark plug wire and the light in the handle of
the screwdriver will flash if the spark plug is operational
Insert the banana plug into the socket in the handle of the probe, the alligator clip must be attached to the chassis or other suitable ground.
To find "live" wires: insert the probe into the wire and a glow of light in the handle of the probe will indicate a "live" wire.
To test light sockets: Touch the probe to the center conductor at the base of the socket (housing).
To operate flashlight: depress the pocket clip.
To use as a continuity tester: Insert the banana plug into the back of the flashlight. Check for "shorted" appliances by attaching the alligator clip to the blade at the end of
the appliance cord. Touch the center to the metallic part of the appliance. Repeat, but using the other blade. If the lamp does not glow either time, the appliance is "shorted" and should be
repaired right away.
Check extension cord: Attach alligator clip to one blade on the male plug. Touch the tester to the other blade. The glowing lamp means the cord is "completed". Checks can also be
made of complete circuits on switches, lights, sockets, spark plugs, auto switches, etc. by merely touching the alligator clip to one terminal and the tester to the other terminal.
Caution: Test circuits with the power off.
