Now that we have covered some basic troubleshooting techniques, what is the best way to find an electrical fault fast? It depends on the nature of the problem.

For a "dead" circuit, the first thing to look for is voltage at the load point. Use your voltmeter or 12-volt test light to check for voltage. If there is voltage, the problem is either a bad ground connection or the component itself has failed. Check the ground connection with your ohmmeter. If the ground connection is good, the fault is inside the component. If there is no voltage in the "hot" wire to the component, then the problem is in the wiring. Trace back through the fuse panel (or relay or circuit breaker) until you find voltage. Now look for an open or short that is preventing the current from reaching its correct destination.

Next comes bad connections. The resistance created by a loose or corroded connection will cause a voltage drop that can have an adverse effect on circuit components. An ohmmeter can be used to check non-powered circuit connections for excess resistance, but a better method is to use a voltmeter to check for a voltage drop across a connection.
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