Tuesday, October 5, 2010

Solving Electrical Problems

Power Probe:
solving electrical problems

Tracking down electrical problems just got easier
By Jefferson Bryant / Photography by Jefferson Bryant
Electrical gremlins will get you every time. Even if you are a seasoned professional, shorts, grounds and intermittent electrical issues are frustrating to chase down.
Once you find the problem the fix is usually easy, but by then half of your hair is on the floor from being pulled out during the search. A multimeter and a test light are required tools for any tool box, but we discovered a tool at the 2009 SEMA show that has changed the way we solve electrical problems. It is called the Power Probe.
At first glance, the Power Probe looks pretty simple, and it is, but what it does is remove a lot of the roadblocks that come up when chasing down wiring problems. A multimeter will tell you if the wire has voltage, but you have to switch leads to determine if it is positive or negative. The Power Probe is powered via the battery (or a 12-volt source) and tells you instantly whether the wire or circuit is live and which side of the circuit you are on, positive or negative. This in itself solves a lot of problems, but there is more.
Since the probe is powered, the tip can provide either a positive or negative charge, allowing you to power a circuit on the fly, without removing the probe first. Just toggle the momentary switch up or down to juice the circuit. If you add the wrong polarity, the buzzer will sound and shut off the juice without popping any fuses. A built-in 10 amp resettable breaker protects the Power Probe from damage as well. The base of the probe has a pigtail attached that provides a constant quality ground, allowing you to assess the ground circuit at the same time.
The Power Probe comes with quite a few accessories, including three bulb socket probes, a fuse panel probe and a nifty backside probe which is great for sliding into the back of insulated terminals. The probe has everything needed to pinpoint problem wires and circuits, but that is only half of the story. The master kit also comes with the ECT2000 circuit tester (which is available separately, too). The ECT2000 is unlike any device you have ever seen — it is an electronic sniffer.
What the ECT2000 does is inject a signal into the circuit via the master unit, then the receiver unit is swept over the circuit (a single wire, circuit or a bundle of wires) and it picks up the signal. Where this is important is the receiver can then find the break in the signal (an open circuit like a break in the wire) or a short circuit. A single wire is easy to trace, but a wire bundle is more difficult.
When wires run parallel or are twisted together electrical signals can jump from wire to wire, just like spark plug wires. This is called “capacitive coupling” and it makes the signal harder to trace as it will jump the open or short. Because of capacitive coupling, the signal is considerably weaker. By holding the receiver further away from the wire bundle, the stronger signal prevails, allowing you to trace the wire. One of the best features of this tool is that it not only sniffs out a problem circuit, but will tell you the direction of the problem. This is done by a pair of lights that show the direction of the problem.
Using the ECT2000 takes a little getting used to, but once you get the hang of it, electrical diagnostics is easy. We used our system to trace a few wires on our 1963 Buick Le Sabre wagon. We used it to locate the fuel sender signal wire inside the wire harness and traced it through to the dash, helping us get the fuel gauge working. The key to using the Power Probe and ECT2000 is the instructional DVD. The paper manual can’t illustrate the ECT2000’s function like a live demo can. You can watch videos of the unit in use on the Power Probe website. In our case, the problem turned out to be a bad connection at the fuel sender itself. If you have ever had to work on an electrical system, this is the tool you need.
1 Choose your weapon: The Power Probe basic kit comes with the power unit, three probes and two piercing probes. The piercing probes open and close by threading the base in and out of the probe unit, which grabs the wire and pierces the wire with a needle probe. It saves your fingers and leaves a much smaller hole in the wire covering.
2 Smart Transmitter: The ECT2000 unit connects to the battery just like the Power Probe. The green wire attaches to one of the probe ends to inject the signal.
3 Follow the light: There are three lights on the receiver; the one to the left notes open circuits, while the two to the right point the direction to shorts. The probe on the end is handy for searching large wire harnesses.
4 Socket probes: The socket probes are another great tool, which help test both the positive and negative sides at once. We found a socket that looked good with a meter, but the bulb wouldn’t work. Using the socket probe, we discovered that was because the housing was bent and not making connection.
5 Accessory plug: Even though the battery terminal connector is 20 feet long, sometimes it is easier to use the accessory plug, which is also an easy way to test them.
6 Power up: With the Probe powered up, we placed it on the battery negative terminal. It lit the “— ” sign, showing a ground.
7 Positive attitude: When we switched it to the positive terminal, the “+” lit up, illustrating a positive connection. The LED display also displays the voltage. You can also induce a positive or negative trigger at the probe by pressing the switch up or down respectively.
8 Grounded circuit: Using the backside probe on the ECT2000, we noted a grounded circuit in the headlight module.
9 Zeroing in: Holding the receiver to the master unit, we locked the signal in so we could trace it.
10 Thataway: Holding the receiver to the wiring bundle, the arrow lit to point us to the ground. While this wire is supposed to be a ground, the process is the same to find issues within other wires. This system works really well; we have used it on several new cars to trace out problem wiring in taillights and trailer plugs, too.



  1. It is pretty incredible how frustrating a system as simple as a positive charge that leaves the battery goes through a device and returns to the neg. side of the battery can leave a person with a good vocabulary with only several 4 letter descriptive words and elevated blood pressure. Good article, thanks.