System Description [12/2015 - ]

The wiper and washer system has the following functions:

1. RAIN SENSING FUNCTION 
   1. General
      • The rain sensing function controls the wiper timing in accordance with the amount of rain that strikes the windshield when the wiper switch is in AUTO.
      • The windshield wiper relay assembly controls the timing based on the signal from the rain sensor.
   2. Rain Sensor

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      1. The rain sensor consists of two LEDs (Light Emitting Diodes) that emit infrared rays, 3 photo diodes that can receive those rays, a lens, and rain sensor tape.

         HINT: 

         If the windshield glass is being replaced, make sure to use new rain sensor tape. Failure to do so will lead to a system malfunction.

         • If no rain is present in the detection area, the infrared rays emitted by the LEDs are all reflected from the outer surface of the windshield glass and are received by the photo diode.
         • If any rain is present in the detection area, a portion of the emitted infrared rays penetrate the windshield glass due to the change in the difference of the index of refraction between the glass and the area outside the windshield (difference between air and water). The ability of the windshield glass to reflect all light back inside changes due to the presence of rain. This change of internal reflection due to the presence of water reduces the amount of infrared rays that are received by the photo diode. The amount of this reduction is then used to determine the amount of rain. Thus, the INT, LO, or HI wiper operation will be selected in order to operate the wipers at an optimal speed and timing.
2. WASHER-LINKED WIPER 
   • When the wiper switch is set to OFF or AUTO and the washer switch is turned on for approximately 0.3 seconds or more, the wipers start operating at low speed at the same time as the washer fluid is sprayed.
   • The wipers operate three times at low speed after the washer switch is turned off.