Automotive, Electrical Diagnosis

How to find a broken wire or open circuit

Todays lesson is how to find a broken wire or open circuit. This can be one of the most frustrating things to troubleshoot. I have used a cable signal tracker from Harbor Freight for many years now to lesson the pain in this process. I have tried many different manufacturers of signal trackers, from the most expensive to the cheapest, and the Harbor Freight Centec is the best you will find. It has a flexible probe that none of the others have. You can select to find continuity or send a tone down the wire. It has a headphone jack and adjustable volume control. This tool only works for a complete open. By that I mean, if there is one single strand of wire still complete, this will send a solid tone from one end of the wire to the other. This will trick you into thinking that the wire is good when in fact it is not. One strand of wire could not possibly carry the current necessary as designed. So you must first test for continuity. If there is no continuity from one end of the wire to the other, you can assume the wire is open (broken). If the wire is open, now is the time to use the signal tracker to help pinpoint the open circuit.

To use the signal tracker, connect the red clip to the wire to be traced., black to ground. Set the transmitter to tone. Turn on the receiver and adjust the volume to a comfortable level. I have found the louder the sound is, the easier it is to hear the first drop of the tone. As soon as the tone drops, that is where the break is. It will take some time to get used to the different tones, but eventually you will be able to pinpoint within one inch of the break. This tool will save you countless hours of troubleshooting and all for the price of only $25. There honestly is no better way to find a broken wire than this method.

Just one more electrical troubleshooting tip from Please come back often for many more indispensable lessons.