Rain Sensor Wiper Function - Rain Sensor Module
WARNING: This page is about a different car, the 2002 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.
The rain sensor module (RSM) is located on the inside of the windshield below the interior rear view mirror and the direct pattern of the wiper blades, if equipped. When the ignition switch is turned to the RUN position, the RSM starts monitoring both the DELAY/WASH and the wiper mode circuits. When the multifunction switch is placed into the INT and AUTO positions, the rain sensor takes control of the mode circuit. In dry conditions the RSM keeps the mode circuit at the correct voltage for the OFF position. In the presence of moisture the RSM directs the mode circuit into individual low pulse, or continuous LOW or HIGH operation, based on the amount of moisture.