Fordracer Posted December 22, 2010 Share Posted December 22, 2010 Here is a good article about locating a draw using voltage drop across a fuse. http://motorage.search-autoparts.com/mot...l/660025?ref=25 Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted December 23, 2010 Share Posted December 23, 2010 Here is a good article about locating a draw using voltage drop across a fuse. http://motorage.search-autoparts.com/mot...l/660025?ref=25 Basing a diag on a differential reading of 0.00050 volts isn't something I am prepared to do. Set your DMM to a mV scale and simply wave the test leads around in the air... the reading on the meter is most likely doing its version of the funky chicken. Given that many ( if not most ) electronic modules will exhibit some sort of "keep alive memory" current draw, how will we distinguish between "good" draw and "bad" draw? Feel free to use this method for determining parasitic draw if you have the cojones for it.... Most of the techs I watch can't seem to remember to check their base voltage before setting out on testing. And most of them don't either do anything to maintain system voltage during testing or fail to regularly check system voltage to ensure it isn't falling intop that region where modules started doing wierd things. Near microscopic voltage variations would be lost on them. One half of a milliVolt? I've used DMMs that can't resolve a reading like that. As an addendum.... I recall another situation from several years ago where a tech was using a voltmeter to find an open fuse.... Even though the truck did have an open fuse, through some kind of fortuitous feedback, the open fuse wasn't discovered until, in absolute desperation (having wasted many hours in diag time), the fuses were visually inspected. Quote Link to comment Share on other sites More sharing options...
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