Possible Wiring Problems

There are only 4 types of electrical problems that can occur in a wire. These 4 are: Open Circuit, Circuit Shorted to Ground, Circuit Shorted to Voltage and Unwanted (extra) Resistance due to corrosion. All 4 are pictured above. The effect that the problem has on the circuit depends on which problem is present and what wire isit in.

All Diagnostic books are written to find opens, shorts to groundand shorts to voltage. These 3 types are easily found with a voltmeter, an Ohmmeter or a testlight.

Unwanted resistance due to corrosion is the hardest to find because the extra resistance usually doesn’t set any fault codes. The extra resistance does cause the circuit to flow less current which causes a voltage drop to or from a sensor, or it reduces current flow to an output (load device) which may cause the output to malfunction. Unwanted resistance due to corrosion usually will not set a DTC because the circuit still functions, just not properly.