Refrigerant Pressure Sensor
WARNING: This page is about a different car, the 1996 Mercedes-Benz C280 and 1996 Mercedes-Benz C220. However, it is still accessible from the selected car via links, so may be relevant.
The refrigerant pressure sensor is located on top of receiver-drier. The sensor protects the A/C system from an under/over charge condition, excessive pressure, and also controls the auxiliary fans. See Fig 1.