Wiper and Washer Systems: Description and Operation
WIPER / WASHER: WIPER AND WASHER SYSTEM: SYSTEM DIAGRAM
1. WIPER AND WASHER SYSTEM
(a) Various switches or sensors are shown as being inputs for the different systems mentioned in the section. Where direct electrical connections do not exist between components, signals may be carried across the different networks (BEAN, CAN) that exist on the vehicle. If a signal needs to travel from a CAN system to a BEAN system, or between different BEAN networks, the gateway ECU allows the signal to travel between these different networks. Some of these different signals can be confirmed or inspected using the Techstream.
(b) The following system diagrams are intended to show the concept of operation, and may not precisely reflect the construction of the system on the vehicle.
Input and Output Signals of Each ECU
HINT
* Wiper operation is controlled by the main body ECU LH (cowl side junction block LH).
* The rain sensor controls the auto wiper function.
SYSTEM DESCRIPTION
1. WIPER AND WASHER SYSTEM
(a) The wiper and washer system may have some of the following functions:
(b) The main body ECU LH controls the wiper system.
(c) Front wiper operation is based on the combination switch and other signals received by the main body ECU LH.
(d) The front controller controls the washer system.
(1) The front controller is located in the No. 2 engine room junction block.
(e) The washer switch operation signal transmitted by the combination switch ECU is received by the main body ECU LH.
2. VEHICLE SPEED-SENSING, ADJUSTABLE INTERVAL FUNCTION
(a) This function controls the intermittent interval of the wipers according to the vehicle speed when the wiper switch is in the AUTO position.
HINT
The vehicle speed sensing intermittent wiper function operates as a fail-safe function if there is a problem with the auto wiper function.
3. VEHICLE SPEED SWITCHING FUNCTION
(a) When the wiper switch is turned to the LO position and the vehicle is stopped, wiper operation is automatically switched to intermittent operation.
(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.
4. STOPPED VEHICLE INTERMITTENT FUNCTION
(a) When the wiper switch is changed to the LO position while the vehicle is stopped, the wiper operates three times in LO. It then automatically switches to intermittent operation with an interval time of approximately 2.5 seconds.
(1) When the intermittent wiper interval adjuster is in the FAST position with the vehicle stopped, the wiper operates in LO.
5. RAINDROP SENSING FUNCTION
(a) General
(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.
(b) 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.
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.
6. WASHER-LINKED WIPER WITH DRIP-PREVENTIVE FUNCTION
(a) When the wiper switch is OFF or AUTO and the washer switch is turned ON for approximately 0.2 seconds or more, the wiper starts a LO operation at the same time as the washer fluid is sprayed.
(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
*: Interval time refers to delay that occurs before the drip-preventative final wiper operation.
7. HEADLIGHT CLEANER SYSTEM
(a) General
(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.
8. WASHER FLUID LEVEL WARNING
(a) Based on the output signal of the washer fluid level warning switch, the front controller can determine that the washer fluid level has dropped below a minimum limit. Using two BEAN systems and the gateway ECU, the front controller will send a signal to the combination meter to cause a warning to illuminate on the multi-information display.