When testing two cables with a multimeter, which one is the negative and which the positive?

Question

Two wires from the car battery, not colour coded, testing with a multimeter/voltmeter how do you tell which one is "negative" (-) and which one is "positive" (+)

Answer 1

Set the VOM meter to DC to read 12 volts or greater

Simply connect the red wire of the VOM to one end of the wire you're testing, and the black wire of the VOM to the other end of the wire.

Numbers on the VOM will be + if you connected the red to the positive wire and black to the negative wire.

Numbers on the VOM will appear with a - sign if you connected the red to the negative wire and the black to the positive wire.

So you don't really need to know about the wire's your testing. The VOM will tell you.

Try it. connect the VOM up one way, then reverse it. The only difference is a sign change.

Answer 2

IF your battery wires are not red/black - then the actual terminals should be a different size.

Another easy way to determine +/- of your car battery is to put your red lead on a battery post and the black lead on a good ground point. You will either have +12V or 0V - telling you which terminal is which.

Answer 3

Red or "+" is always positive, it is usually the easiest to access, the "+" sign will be on the battery

Answer 4

red is + + goes to starter...- goes to ground