In the expansion valve A/C system, the warm liquid is then passed through a receiver-drier which removes moisture (via a desiccant in the drier) from the refrigerant to maximize the efficiency of the heat exchange capability of the refrigerant. On 944s, the receiver-drier is a small canister (probably with a sightglass on top) located near behind the driver's side headlight (LHD cars). No phase change occurs as the refrigerant passes through the receiver-drier. From there, the refrigerant is then passed through the expansion valve. The expansion valve has a sensing line that is attached to the suction of the A/C compressor. The expansion valve senses the pressure at the suction of the A/C compressor and modulates to maintain the pressure at the compressor suction. On 944s, the expansion valve is located near in the passenger's footwell (LHD cars) near the center console next to the firewall.