Which battery cable is the negative on a 2000 Nissan frontier?

The negative battery cable is usually connected to the metal frame of the car, while the positive battery cable is connected to the starter motor. On some vehicles, the negative cable may have a black cover with a minus symbol, while the positive cable may have a red cover with a plus symbol. To be sure, you can use a multimeter to test the cables; the negative battery terminal will show a negative voltage, while the positive battery terminal will show a positive voltage.