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Home >> Lexus >> 2019 >> LS 500 Base, AWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Wiper/Washer Systems >> Wiper System / Washer System - Diagnostics - Introduction >> Wiper And Washer System >> System Description [12/2017 - 10/2020] >> System Description [12/2017 - 10/2020]
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System Description [12/2017 - 10/2020]

  1. FRONT WIPER AND WASHER CONTROL FUNCTIONS 
    Control/Function Description
    Wiper speed regulation Maintains the default speed of the front wipers even when the supply voltage or resistance changes.
    Door open linked wiper suspend function Stops the front wipers when the windshield wiper switch assembly is in the AUTO position, the shift lever is in P and the driver door or front passenger door is open.
    HINT: 
    • The front wipers stop at their lowermost position for 0.3 seconds, and then move to the park position.
    • AUTO control restarts when the door is closed.
    Wiper speed HI to LO transition control Smoothly controls the change in speed of the wipers when the wiper speed is switched from HI to LO.
    Service position control When the windshield wiper switch assembly is held in the MIST position for 2 seconds or more within 45 seconds of turning the engine switch off, stops the front wipers near the upper reverse position.
    HINT: 
    • The front wipers can be returned from the service position by turning the engine switch on (IG) and operating the front wipers by moving the windshield wiper switch assembly to any position.
    • When the windshield wiper switch assembly is moved to the MIST position when the front wipers are in the service position, the front wipers will return to the park position.
    • The front wipers must be in the service position when locking back* the front wipers.
    • When the front wipers are returned from the service position, the wipers operate at a slow speed for the first cycle to minimize damage to the engine hood if contact with a front wiper arm occurs due to it being in the lock-back position. Also, if a front wiper arm contacts the engine hood, the will be are stopped after being moved a short distance in reverse.
    Engine hood interference damage reduction function
    • Operates the windshield wiper motor at a slow speed for the first cycle when the front wipers are returning from the service position to minimize damage if a wiper arm in the lock-back position contacts the engine hood.
    • Moves the front wipers a short distance in reverse if a wiper arm in the lock-back position contacts the engine hood and the windshield wiper motor locks up.
    Self locking control Holds the wipers in the park position when the engine switch is on (IG).
    Washer control The washer fluid is sprayed in the direction that the wiper is moving. Controls when the washer fluid is sprayed and stopped while windshield wiper switch assembly (washer switch) is turned on. In addition, the washer fluid spray time changes according to the vehicle speed and outside temperature.
    Protection mode Monitors the current, speed and temperature of the front wiper motor in order to protect the system.
    HINT: 
    • Overload protection, which operates in situations such as when the front wipers and operates them in INT is dry, reduces the speed of the front wipers and operates them in INT in order to reduce wear.
    • Snow protection operates when accumulated snow at the extremities of the front wiper movement interferes with operation. In this situation, the front wipers will temporarily stop and push the snow. If the snow cannot be cleared, the wipers reverse direction and then continue.
    • Excessive load protection operates when a foreign object near the center of the wiper movement interrupts the wiper movement. In this situation, the wipers temporarily stop and push the foreign object 4 times. If the foreign object cannot be cleared, the wipers will stop.
    MIST function Operates the wipers in LO when the windshield wiper switch assembly is held in the MIST position.
    Auto operation Operates the wipers as requested by the rain sensor when the windshield wiper switch assembly is in the AUTO position.
    Vehicle speed linked wiper intermittent operation control Controls the delay of the wipers when the windshield wiper switch assembly is in the INT position.
    HINT: 
    • The period of delay is controlled by the auto sensitivity adjustment switch on the windshield wiper switch assembly.
    • The period of delay changes in accordance with vehicle speed.
    • When the windshield wiper switch assembly is in the INT position and the vehicle is stopped, the wipers operate for 1 cycle when the vehicle starts off.
    • When the auto sensitivity adjustment switch on the windshield wiper switch assembly is moved to a faster position, the delay is reset and control begins according to the new setting.
    Washer cooperation
    • When windshield wiper switch assembly (washer switch) is on for approximately 0.3 seconds or more and the wiper operates for 1 round trip or less:

      If the windshield wiper switch assembly (washer switch) is on for approximately 0.3 seconds or more, the wiper operates at a speed slower than LO after 0.5 seconds elapse. Check that the wiper operation is performed twice in LO after the windshield wiper switch assembly (washer switch) is turned off.

    • When windshield wiper switch assembly (washer switch) is on for longer than 1 round trip:

      The wiper operation continues until the windshield wiper switch assembly (washer switch) is turned off. Check that the wiper operation is performs 3 times after the windshield wiper switch assembly (washer switch) is turned off.

    HINT: If the windshield wiper switch assembly (washer switch) is on continuously for 40 seconds or more, the system determines a malfunction and the washer operation stops.
    NOTE:

    If the front windshield wiper switch assembly (washer switch) is operated for 40 seconds or more, operation of the washers is stopped to prevent burnout of the washer motor and pump assembly, and the wipers return to the park position.

    Drip prevention wiper function 3 seconds after washer cooperation operation ends, operates the front wipers for 1 cycle to remove any remaining washer fluid from the windshield glass.
    HINT: 
    This function only operates when the vehicle is stationary or when the vehicle is being driven at less than 7 km/h (4 mph).
    Vehicle stopped wiper control If the vehicle is stopped with the windshield wiper switch assembly in the LO position, the front wipers will operate for 3 cycles and then automatically change to intermittent operation with an interval of 2.5 seconds.
    1. *: Function to allow the wiper arms to be folded back, such as when replacing the wiper blade.
  2. OTHER FUNCTIONS 
    Control/Function Function Description
    Headlight cleaner control (w/ Headlight Cleaner System) With the engine switch on (IG) and the headlights illuminated, the windshield wiper switch assembly (washer switch) operates the headlight cleaner motor and pump assembly the first time and every fifth time it is turned on, and washer fluid is sprayed from the headlight washer actuator sub-assembly for approximately 1 second.
    Washer fluid level low warning Displays "Windshield Washer Fluid Low" on the multi-information display in the combination meter assembly when the washer fluid level is low.