System Description

Fig 1: Identifying Engine Room Junction Block

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. The front controller is located in the No. 2 engine room junction block.

HINT: 

The vehicle speed sensing intermittent wiper function operates as a fail-safe function if there is a problem with the auto wiper function.

1. When the vehicle stops while driving with the wiper switch in the LO position, the wiper operates twice in LO. It then switches to intermittent operation with an interval time of approximately 2.5 seconds. If the vehicle starts moving during this intermittent operation, the wiper automatically returns to LO operation.
2. When the intermittent wiper interval adjuster is in the FAST position with the vehicle stopped, the wiper operates in LO.

1. When the intermittent wiper interval adjuster is in the FAST position with the vehicle stopped, the wiper operates in LO.

1. The raindrop sensing function controls the wiper timing in accordance with the amount of raindrops that strike the windshield when the wiper switch is in the AUTO position.
   • The main body ECU LH adjusts the wiper timing based on commands from the rain sensor. These adjustments are based on vehicle speed and a determination of the vehicle driving and stopping conditions during automatic operation.
   • The rain sensor sends a wiper operation instruction signal to the main body ECU LH that is based on the amount of rainfall.
   • The rain sensor sensitivity can be adjusted by operating the adjustment ring on the windshield wiper switch.
   • When the wiper switch is in the AUTO position, the rain sensor determines the wiper speed based on vehicle speed received from the combination meter and the amount of raindrops. The rain sensor sends a signal to the main body ECU LH. The main body ECU LH will vary the wiper speed in accordance with the signal received from the rain sensor.

1. The rain sensor consists of 4 LEDs (Light Emitting Diodes) that emit infrared rays, a photo diode that can receive those rays, a lens, and rain sensor tape.
   Fig 2: Identifying Rain Sensor Tape

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   HINT: 

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

   • If no raindrops are 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 raindrops are present in the detection area, a portion of the emitted infrared rays penetrates 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 the emitted rays back inside change due to the presence of raindrops. This 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 raindrops. Thus, this function selects the INT, LO, and HI wiper operation in order to operate the wipers at an optimal speed and timing.
     Fig 3: Identifying Detection Area

     Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. The wipers will operate three times in LO after the washer switch is turned OFF.
2. The front wipers will operate three times after the front washer switch has been operated continuously for more than 40 seconds, and then stop.
3. As shown in the following table, the wiper operates once more after an interval time (between 3 to 7 seconds) determined based on the vehicle speed so that any washer fluid drips are wiped away. The speed signal used for this function is sent by the combination meter, and received by the main body ECU LH.
   INTERVAL TIME TABLE
   
   

   Vehicle Speed (mph (km/h))	Interval Time*
   0 to 36.7 (0 to 59)	Approx. 3 sec.
   37.3 to 49.1 (60 to79)	Approx. 5 sec.
   49.7 to 73.9 (80 to 119)	Approx. 7 sec.
   74.6 to 98.8 (120 to 159)	Approx. 5 sec.
   99.4 to 105 (160 to 169)	Approx. 3 sec.
   105.6 or more (170 or more)	No operation

   *: Interval time refers to delay that occurs before the drip-preventative final wiper operation.

1. The headlight cleaner system sprays washer fluid on the headlight lenses to clean them.
   • The headlight cleaner control relay controls this system.
   • The headlight cleaner system can be operated by pushing the headlight cleaner switch when the headlights are ON.
   • The headlight cleaner system also operates when the headlights are ON, and the front wiper washer system is operated.
   • The headlight cleaner system will not operate when the daytime running light system is operating.