If you use a testlite, the pointed end you use to probe the wire if needed/voltage. The other end may have an alligator clip on it, you touch that end to ground/metal part of vehicle. The testlite has no polarity, you can use either end for voltage or ground. If the lite comes on, you have voltage and ground. The best thing you can do is get a testlite or multimeter, read the directions if any and just play with them, take readings.
With the digital multimeter, the red lead is voltage and the black lead is ground.
Monday, March 31st, 2014 AT 1:31 PM