Very often we find ourselves striping wires, cutting wires, splicing, or simply removing a cigarette lighter plug, to then hardwire the wire. so which is negative, and which is positive? take a look at the wire, and you will notice a solid, dashed, or otherwise "marked" wire. That wire is your POSITIVE(+). The other wire is negative and can go to the negative terminal of the battery or otherwise "grounded" to anything metal on the car. Words alone are not a "marking". there will be ribs, lines, dashes, or some form of clear marking.