From my "Dawn of Time" electronics schools we were told....Electrons have a negative charge. Therefor electron flow or current flow is negative to positive. But in the real world using the number line that we learned in grammer school only positive numbers really exist. In other words, you can't take 2 negative apples and give to Johnnie. To make a complicated idea simple in order to train electronics people quickly in WWI and II and such, they invented "positive logic", where current flow is postive to negitive. Today we call it "hole flow". Little tricks like turning the colors of the voltmeter leads around and reversing the (+) and (-) markings on capacitors, etc. and you got it. It really doesn't matter when doing electrical work on trucks other than we need to ALL be the same page as to what is positive and negative. Hope this helps.
