the invention relates to a heating / cooling circuit for a motor vehicle comprising an evaporator for cooling air to be fed into an interior space , a heat exchanger for heating said air to be fed into the interior space , an external heat exchanger comprising a compressor for transporting coolant , a first expansion organ , allocated to the evaporator , a second expansion organ , allocated to the external heat exchanger and coolant conduits , via which the aforementioned components are interconnected . the compressor , the external heat exchanger and the second expansion organ constitute a de - icing circuit of the inventive circuit .