Dan Sullivan Fundamental Electrical Troubleshooting Jun 2026

His legacy is a generation of technicians who no longer fear electrical problems. They understand that electricity follows rules, and if you know the rules—and follow the logic—the circuit will always tell you exactly what is wrong.

You haven't truly tested a circuit until you’ve tested it while it’s trying to do work. Tools of the Trade: Beyond the Multimeter dan sullivan fundamental electrical troubleshooting

Most technicians are taught to use a voltmeter to test for the presence of voltage. They will probe a connector, see 12.6 volts, and declare the circuit "good." Sullivan points out the fatal flaw in this logic: this method only tests for available voltage, not the circuit's ability to carry a load . His legacy is a generation of technicians who

A wire can be corroded to the point where only a single strand of copper remains. It will still show 12.6 volts on a multimeter because the multimeter draws almost zero current. However, as soon as a load (like a starter motor or headlight) is applied, that single strand cannot carry the current, and the circuit fails. Tools of the Trade: Beyond the Multimeter Most