Abstract: In order to provide a method for initiating a defrosting process of a heat exchanger of a heat pump of a motor vehicle, which method is insensitive to external influences and can also be used in combination with other methods, wherein the heat exchanger and a coolant heat exchanger of a cooling circuit of the motor vehicle are arranged in a common air path, a coolant outlet temperature of a coolant from the coolant heat exchanger is determined, and a state of icing of the heat exchanger is determined using the coolant outlet temperature, and initiating a defrosting process of the heat exchanger if icing of the heat exchanger is determined.

Abstract: In order to provide a method for initiating a defrosting process of a heat exchanger of a heat pump of a motor vehicle, which method is insensitive to external parameters influencing the air flow through the evaporator, and with which method unnecessary defrosting processes can be avoided, wherein a fan is assigned to the heat exchanger, wherein a power consumption and/or a speed of the fan is monitored, a defrosting process is initiated when the power consumption and/or the speed exceeds and/or falls below a threshold value, and the threshold value is determined as a function of a parameter, wherein the parameter is an indicator of a current relative air speed of the ambient air in relation to the motor vehicle.