Contactor Position and Failure Detection System

A method for distinguishing faults for at least one battery module on a voltage bus, the at least one battery module being switchable between an ON state and an OFF state, includes: commanding a positive contactor of the at least one battery module to open; determining whether a switch of the positive contactor indicates the positive contactor is open or closed, and: if the switch of the positive contactor indicates the positive contactor is open, commanding a negative contactor of the at least one battery module to open, or if the switch of the positive contactor indicates the positive contactor is closed, comparing a bus voltage of the voltage bus to a first bus voltage threshold, and: if the bus voltage is less than the first bus voltage threshold, commanding the negative contactor to open.