Here, we will illustrate a problem you may encounter when tracing an open circuit in an open harness. This is much different than tracing a complete circuit. When both ends of the harness are floating, it means both ends are connected, neither to ground nor hot. When injecting an open circuit signal into the middle circuit what happens is that by means of capacitance, the open circuit signal couples with the neighboring wires and they emit open circuit signals too.
As you can see, floating circuits make it very difficult to trace the preferred isolated open circuit. Now to prevent the signals from coupling to neighboring wires, you will need to supply the neighboring wires with some potential of negative by perhaps clipping a ground wire to them. Or you can turn the key on and this can supply the other circuits with a positive. So keep in mind that the open circuit signals can couple into neighboring open wires if they are not tied to some potential of ground or positive.
30 сен 2024