a central air outlet 115 opening into the central region of the passenger compartment of the automobile and side air outlets 116 and 117 opening respectively into the opposite side regions of the passenger compartment dampers 118 to 122 are disposed respectively near the air outlets 112 113 115 116 and 117 referring to fig2 showing a refrigeration circuit through which a refrigerant is circulated included in the automotive air conditioner a compressor 201 with a built in electric motor not shown for compressing a refrigerant is contained in a sealed container 202 the discharge port of the compressor 201 is connected to a selector valve 204 by a discharge line 203 the selector valve 204 delivers the refrigerant discharged from the compressor 201 to the internal heat exchangers 109 and 110 or to an external heat exchanger 205 the internal first heat exchanger 109 and the external heat exchanger 205 are interconnected by a refrigerant line 206 a cooling capillary tube 207 and a heating capillary tube 208 are provided in the refrigerant line 206 and check valves 209 and 210 are connected in parallel to the capillary tubes 207 and 208 respectively the second internal heat exchanger 110 provided in the second duct unit 130 is used principally for dehumidification a dehumidifying capillary tube 211 is disposed between the second internal heat exchanger 110 and the first internal heat exchanger 109 a bypass circuit 212 provided with a reversible solenoid valve 213 is connected in parallel to the dehumidifying capillary tube 211 the reversible solenoid valve 213 always allows the flow of the refrigerant from the first internal heat exchanger 102 toward the second internal heat exchanger 110 the reversible solenoid valve 213 allows the reverse flow of the refrigerant only when.