Magazine for the auto service professional
Issue link: http://asp.epubxp.com/i/684411
21 | ASP June 2016 Circle 106 on Reader Service Card Technical between any two points in that circuit, even if the two test points are very close together. Te voltage drop across a fuse might be only a few tenths of a millivolt, but if it's more than zero, that means current is fowing through the fuse. We found a chart published by the folks at Power Probe that lists voltage drop across standard fuses for the amount of current fowing through the fuse. For instance, in the photo on page 20 we see 8 millivolts fowing through a 10-amp fuse. According to the chart, this means 1.039 amps of current is fowing through that fuse. While that infor- mation can be useful, it's not really necessary to know the actual number when looking for parasitic current draw. All we're looking for is any fuse with a voltage drop greater than zero with the ignition switch turned of. One problem with checking circuits this way is that you can't always do it with all the doors closed. For instance, the fuse panel in that same photo is inside the car, and opening any door turns on the interior lights and wakes up some of the control units. However, we noticed after a few minutes that only the