How to Use a Power Probe

by Heather Finch

The Power Probe and Power Probe II are easy-to-use diagnostic tools for car electrical systems from 6 to 24 volts. While multimeters have several functions and dials, the Power Probe only has an on/off switch, making it faster to diagnose problems with your car engine. The Power Probe II has an optional audio feature for situations where the LED is not clearly visible. If you are not familiar with the electrical component of a car engine, you will need some help in diagnosing your problem.

Step 1

Insert the battery clips into the Power Probe. Put the clamp with the red cord on the positive terminal of your battery and the clamp with the black cord on the negative terminal of your battery or on a ground. Turn the power switch to positive. You should see a red light, and if you have a Power Probe II, you should hear a high-pitched tone. Turn the power switch to negative. You should see a green light and hear a low-pitched tone.

Step 2

Test polarity by placing the Power Probe tip (the point coming out of the unit) on the circuit. A red light with a high-pitched tone will indicate a positive circuit, while a green light with a low-pitched tone will indicate a negative circuit. An open circuit will show no light or play any sound.

Step 3

Test continuity by disconnecting the wire or component you need to test from the electrical system and touching the tip and the auxiliary ground test lead (the other cord with a metal tip) to that part. If there is continuity, the light will be green.

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