Vehicle air-conditioner safety device, and control method thereof

A vehicle air-conditioner safety device for a vehicle air-conditioner having a heating device, comprising:

• a controller configured to
• determine when an abnormality has occurred in the heating device that heats coolant with a heater, whether the abnormality is a restorable abnormality or a non-restorable abnormality,
• determine when the abnormality is determined as being the restorable abnormality, whether or not the restorable abnormality is removed,
• prohibit heating by the heater when the restorable abnormality has occurred and prohibit heating by the heater when the non-restorable abnormality has occurred,
• restore heating by the heater when the restorable abnormality is removed after heating by the heater is prohibited due to occurrence of the restorable abnormality, and
• prohibit heating by the heater, when the non-restorable abnormality has occurred, even when the restorable abnormality has been removed,
• wherein
• the restorable abnormality includes an abnormality in which a temperature of at least one of a switching device, which allows or interrupts flow of current to the heater, or the heater becomes higher than a predetermined temperature, and
• the non-restorable abnormality is an abnormality in which an input signal and a driving signal of a transistor as the switching device do not match.