I am probing two pins on a custom circuit board which I believe have been shorted somewhere and am attempting to measure the resistance between these pins with an Agilent 34401A multimeter. When trying to get a definitive resistance measurement, the readout of the multimeter does not settle on a single value, as it would if measuring a passive resistor. Instead, it jumps around between displaying values of 5ohms, 40 ohms, 25ohms, etc.
When measuring these pins on a unit that does not have the short, the readout is between 2-4kOhms, but also does not home in on a single value and instead jumps around in this range.
Is there any conventional knowledge or perhaps a rule of thumb as to why this is happening, or is it an issue that requires more detailed knowledge of the specific circuitry?