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Originally Posted by sportpsyc
So to re-state your instruction for clarity, I take the pos. battery cable off, and put the negative DMM lead on the negative battery post (or on the frame for that matter since the neg. battery terminal just grounds to the frame anyway...),
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Both for testing a diode AND tracing a ground, the meter should be set of OHMS, not volts.......but the positive side of the battery MUST be disconnected or you will let the smoke out of your meter !!!
If you are going to try to trace grounds with the ohm-meter, put one lead on the (-) battery post or the cable that connects there. DO NOT connect it to the frame. We are, after all, maybe looking for something that is connected to the frame but NOT to the negative battery.
And I've got to mention again (appologies to 5th) that trying to trace the grounds with a ohm-meter may not be the best way......because of secondary, back-door grounds. If you DO that, be suspicious of any reading above 0 ohms. Calibrate the meter by shorting the leads together to be sure a dead short actualy reads 0.
As long as we are doing this, maybe I should define: secondary, back-door ground. :roll:
It is a path to ground through another branch of a circuit or through another device when the physical ground is absent.
If, for instance, there are several things in close physical proximity that all need a ground, it is common to tie them all together and the run a heavier wire to the frame ground. If that common wire goes open, the negative side of the devices are still tied together. Sometimes one, or more, of those devices actually supplies a partial path to ground........so that a tiny bit of current still flows.....and an ohm-meter will still give a reading........although not enough current to make things work right and the meter will not read a "good" zero.
Whew. Sure hope "we" get this fixed soon. All this worry and effort is tiring me out !!!! :lol:
