The last few editions of “The Trainer” have focused on the voltage drop electrical troubleshooting technique. In the February 2016 edition we’re going to look at the most common faults you’ll encounter when isolating the cause of an electrical concern.
What are those, you ask? Obviously, one of the first that comes to mind is an open in the path anywhere in the circuit. Electrical 101 teaches us that an electrical circuit needs a complete path for current to flow. The result of an open circuit is kind of obvious, too. The circuit will not function.
Next is one of the more common issues you’ll face – high resistance in the circuit. This can be on either side of the load or even in the load and takes many forms. Adding resistance under a given voltage reduces current flow (basic Ohm’s Law) and the load will work sluggishly or not at all.
What about lower resistance in the circuit? There are a couple of scenarios for this situation. One that comes to mind is an internal short in a coil of some type; an ignition coil, injector winding, or window motor are some examples. When that happens, current will increase but the component will not function or function weakly. Another example is one you may or may not have already thought of yourself – the short circuit, or a short to ground in the positive side of the circuit. That certainly will cause current to rise!
Current can be a great tool in helping locate the cause of electrical concerns and mated with the voltage drop techniques you’ve learned to date, would go a long way in helping you master the are of electrical diagnosis. Watch this month’s “Trainer” to see how!
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