There is a belief that the more functions a tool performs, the poorer it performs those functions. One exception to this theory is the Power Probe III (PP3)—a versatile, 12- to 24-volt circuit tester/test light. Computer safe, voltage sensing and short protected, the PP3 can be used to check polarity and continuity. Circuits are identified both audibly (high or low pitch tone) and visibly on a backlit LCD display along with a red or green LED indicator. The unit also has two built-in white LED illuminators which act as a handy flashlight.
The cleverest feature of the Power Probe III is its ability to conduct positive or negative current at the probe tip. Once connected to the vehicle, either by battery terminal clips or a DC (cigarette lighter) plug, the PP3 becomes a 10-amp power source. There is no time wasted with jumper leads; simply complete the circuit with the PP3 by flipping the unit’s switch (up for power, down for ground). The unit’s built-in circuit breaker prevents overload, and the display will let you know if it trips.
This Power Probe
Mode is particularly handy for bench-testing video systems and configuring LED lightheads and other warning system components prior to install. Because you are able to use the host vehicle’s power source, you can determine if there might be any low-voltage problems or electrical interference.
Bad ground connections play havoc with warning system components and can be one of the more frustrating electrical problems to diagnose. The Power Probe III lets you determine bad grounds instantly. There’s no need for a voltage drop test; instead, use the PP3 to power the grounded contact. If the circuit breaker trips, the ground is good. Following shorts is just as easy, and you won’t have to constantly replace fuses. Just press the circuit breaker reset button to get back to work.
Continuity testing with the PP3 lets you check resistance to ground at two levels: more than 2K Ohms and less than 20K Ohms, useful for testing solenoids; and less than 2K Ohms, for relay coils and wiring. The LCD and green LED indicator inform the tech of the resistance level.
The Power Probe III also has Negative Peak and Positive Peak Modes. The Negative Peak Mode monitors a positive circuit to capture its lowest voltage, while Positive Peak Mode captures the highest detected voltage. Peak to Peak Mode is also available to measure the difference between the positive and negative peak voltages. Each mode is easily selected using the multifunction mode button. Because the LCD displays the voltage peak results until you reset it, the PP3 can be used remotely, allowing you to work how and where you need without constantly monitoring the PP3.
The PP3 has interchangeable probe tips in 3- and 9-inch lengths, an alligator clip tip, two sizes of piercing probe tips, a fuse blade tip, and a terminal back probe tip. All tips connect using standard, gold-plated, 4mm banana plugs, so you can even make your own custom tips using parts from Radio Shack. Other Power Probe III accessories include flexible extension leads of various lengths for the probe tip, 20-foot power lead extensions, 4mm male and female adaptors, and blow-molded plastic cases. There are also bulb adaptors to connect the PP3 to the vehicle light circuits using the bayonet or wedge-type light bulb sockets.
The basic Power Probe III retails around $150. Several kit packages are available. Add up the cost of the tools it replaces—jumper leads, multi-meters, test lights, computer-safe circuit testers, etc.—and it becomes clear that you are getting a great value. See the company’s Web site for more information, including specifications, demonstration videos and a complete user’s manual. Matthew Ayers is the owner of Command & Control Installations in Sevierville, Tenn. He is currently a lieutenant with the Sevierville Police Department and may be reached at C2installs@charter.net.