Wiper/Washer System Description and Operation STS
Wiper/Washer System Components
The Wiper/Washer System consists of the following components:
| • | Windshield wiper/washer switch |
| • | Windshield wiper/washer module |
| • | Instrument panel module |
| • | Outside moisture sensor |
| • | Windshield/headlamp washer motor assembly |
| • | Windshield washer fluid level switch |
| • | Headlamp washer fluid pump relay |
| • | HEADLAMP WASHER Circuit Breaker 30 A |
Modes of Operation
The normal wiper system function positions are as follows:
The manual low speed and manual high speed wiper modes are continuous wiper operations as selected via the wiper switch.
Automatic Modes of Operation
The rain sensing windshield wiper system function positions are as follows:
Automatic low speed and automatic high speed wiper modes are continuous wiper operations that are controlled by the outside moisture sensor. Automatic low and high speed operation is utilized when the amount of precipitation on the windshield exceeds the
automatic delay or low threshold.
Moisture Sensitive Wipers
The outside moisture sensor monitors moisture accumulation on the windshield and uses a windshield wiper/washer switch status input to provide wipe commands to the windshield wiper/washer module. The DELAY positions on the wiper/washer switch are used
to activate the AUTOMATIC rain sensing operating mode. They are also used to adjust the level of sensitivity to moisture accumulation, which determines the dwell time for commanding a wiper motor wipe cycle.
Battery positive voltage is supplied to the outside moisture sensor through the accessory voltage circuit and RAIN SSR fuse located in the underhood fuse block. The sensor is grounded through the ground circuit and G402. Whenever the ignition is in the
run or accessory positions, the windshield wiper/washer module sends the wiper/washer switch status using a pulse width modulation (PWM) signal through the moisture sensor signal 1 circuit to the outside moisture sensor. When a wipe cycle is needed, the
moisture sensor sends a PWM voltage signal through the moisture sensor signal 2 circuit back to the wiper/washer module requesting the wiper operation.
The outside moisture sensor uses the moisture sensor signal 2 circuit to command wiper motor wipe cycles and to confirm the moisture sensor signal 1 is being received. If at anytime communication between the moisture sensor and wiper/washer
module is lost, the wiper/washer module will use the inputs from the windshield wiper/washer switch in the delay positions to operate the wiper motor at continuous variable delay intervals.
Power and Grounds
Accessory voltage is supplied to the windshield wiper/washer module from the WPR MOD fuse located in the underhood fuse block. This voltage allows the wiper/washer system to operate only when the ignition switch is in the Accessory or On positions. The
module is grounded through the module ground circuit and G101.
Accessory voltage is supplied to the windshield wiper/washer switch from the WPR SW Fuse located in the underhood fuse block.
Wiper/Washer System Operation
The windshield wiper/washer module is part of the windshield wiper motor cover and controls wiper motor operation. The accessory voltage supplied to the windshield wiper motor assembly is used to operate the wiper motor in all modes. The windshield wiper
motor is a 2 speed motor and is operated at low speed in all modes except HIGH. When the wiper/washer switch is activated, battery voltage is applied through the switch contacts, a series of resistors, and through the wiper switch signal circuits to the
wiper/washer module. The voltage level of these signal circuits determine the windshield wiper/washer modes of operation. The following is a list of wiper/washer modes of operation:
| • | Manual Low Speed:
When the wiper/washer switch is in the LOW position, battery voltage is applied through a 24K ohm resistor and the windshield wiper switch signal 2 circuit to the module. Battery voltage is also
applied through the windshield wiper switch signal 1 circuit to the module. The reduced voltage from the wiper switch signal 2 circuit and voltage from the wiper switch signal 1 circuit indicates the manual low request. In response to these
signals, the wiper/washer module applies voltage to its internal wiper motor LOW speed terminal and the wiper motor runs in the manual LOW speed mode. |
| • | MIST:
Windshield wiper/washer system MIST operation is identical to LOW operation, as described above, except that the MIST switch is a press and release type. When the wiper switch is moved to the MIST position and released,
low speed wiper motor operation is started and will continue until 1 cycle is complete. If the wiper switch is moved to the MIST position and held, the windshield wiper motor will operate in the LOW mode until the switch is released. |
| • | DELAY:
Windshield wiper DELAY operation is also a low speed wiper motor function, but with a variable delay interval between the wiper motor cycles. The DELAY interval is controlled through a series of resistors within
the wiper/washer switch. During DELAY wiper operation the wiper switch signal 2 circuit is at the same voltage level used for LOW speed operation, but the wiper switch signal 1 circuit voltage is reduced through the DELAY resistors. The windshield
wiper/washer module uses a capacitor that is fed by the wiper switch signal 1 circuit to determine the frequency of the low speed wiper motor cycles. When the wiper switch signal 1 circuit is at a high voltage level as in the LOW switch position,
the higher voltage charges the capacitor fast, causing a delayed, but continuous LOW speed wiper motor operation. The DELAY switch position indicating the longest interval between wiper motor cycles, is the switch position with the highest resistance, resulting
in low voltage on the wiper switch signal 1 circuit. This low voltage charges the capacitor slowly, causing a long delay interval between wiper motor cycles. As the DELAY switch is turned to positions indicating more frequent wiper cycles, the resistance
through the wiper/washer switch is reduced and the wiper switch signal 1 circuit voltage increases. When the wiper switch signal 1 circuit voltage increases the capacitor charges faster and the delay interval between wiper motor cycles decreases. |
| • | Manual HIGH Speed:
When the wiper switch is placed in the HIGH position, battery voltage is applied through the switch contacts and the wiper switch signal 1 circuit, wiper switch signal 2 circuit, and the
high speed signal circuit to the wiper/washer module. During HIGH speed wiper operation, the wiper switch signal 1 and signal 2 circuits are at the LOW speed signal voltages, but, the LOW speed signal circuit inputs to the wiper/washer module are
overridden by the active HIGH speed signal circuit. In response to this signal, the wiper/washer module applies voltage to its internal wiper motor high speed terminal and the wiper motor runs in the manual high speed mode. |
| • | WASH:
The outside moisture sensor monitors the WASH switch to determine if the wash function is selected. When active, the moisture sensor uses this information to ignore the wash water input to the algorithm. During windshield
wiper/washer system WASH operation, the wiper/washer module controls the operation of both, the wiper motor and the windshield washer pump. |
| | When the WASH switch is pressed, battery voltage is applied through the switch contacts and the windshield
wiper/washer switch signal 2 circuit to the wiper/washer module indicating the wash command. The wiper/washer module then applies battery voltage to its internal wiper motor low speed terminal and the windshield washer pump control circuit for a minimum
of 3.5 seconds or as long as the WASH command is active, followed by approximately 6 seconds of wiper motor operation. |
| • | PARK or OFF:
Windshield wiper motor park operation is controlled by the wiper/washer module using an input from the PARK switch within the wiper motor assembly. When the windshield wiper/washer switch is turned to the
OFF position while the wiper motor is somewhere in mid-cycle, the wiper/washer module will continue to operate the wiper motor until the wipers reach the PARK position. |
| • | Automatic Delay:
The wipers are normally in the PARK position. The moisture sensor determines the dewell time appropriate for the amount of precipitation on the windshield after considering the wiper switch SENSITIVITY
setting. When moisture accumulation indicates a wipe is needed, the moisture sensor signals the wiper/washer module to clear the precipitation from the windshield. For all automatic delay operations the outside moisture sensor commands the wipers to operate
in LOW speed for one wipe. |
| • | Automatic Low:
Automatic LOW speed operation is utilized when the amount of precipitation on the windshield exceeds the automatic delay threshold. With a steady amount of precipitation on the windshield, the algorithm
written for this threshold will prevent cycling between automatic delay and automatic LOW speed operation. |
| • | Automatic High:
Automatic HIGH speed operation is utilized when the amount of precipitation on the windshield exceeds the automatic low threshold. With a steady amount of precipitation on the windshield, the algorithm
written for this threshold will prevent cycling between automatic LOW and automatic HIGH speed operation. |
Heated Washer Nozzles
The purpose of the heated washer nozzles is to prevent nozzle freeze-up in cold weather. With the ignition in the ON position, battery positive voltage is applied to both washer nozzles from the 10 A WASH NOZ fuse located in the underhood fuse block.
The washer nozzles are permanently grounded to G101. They are in operation at all times when the ignition is in the ON position, nothing else controls their operation.
Check Washer Fluid Message
The CHECK WASHER FLUID message is controlled by the instrument panel module (IPM) using an input from the washer fluid level switch. With the ignition is in the ON position, the IPM applies ignition voltage through an internal resistor and the windshield
washer fluid level signal circuit to the windshield washer fluid level switch. The IPM then monitors this voltage to determine the washer fluid level. With the washer fluid above a determined level, the washer fluid level switch is open and the IPM detects voltage
on the signal circuit. When the washer fluid reaches the point where the driver should be informed that the washer fluid is low, the washer fluid level switch closes. When the washer fluid level switch is closed, the washer fluid level signal circuit is pulled
low and the IPM displays the CHECK WASHER FLUID message on the driver information center (DIC). In order to prevent the CHECK WASHER FLUID message from being displayed while sloshing is occurring in the washer fluid container, the IPM is programed with a 1 minute
delay before changing states of the CHECK WASHER FLUID message during an ignition cycle.
Wiper/Washer System Description and Operation STS-V
Wiper/Washer System Components
The Wiper/Washer System consists of the following components:
| • | Windshield wiper/washer switch |
| • | Windshield wiper/washer module |
| • | Rear integration module (RIM) |
| • | Outside moisture sensor |
| • | Instrument panel module (IPM) |
| • | Windshield/headlamp washer motor assembly |
| • | Windshield washer fluid level switch |
| • | Headlamp washer fluid pump relay |
| • | HEADLAMP WASHER Circuit Breaker 30 A |
Modes of Operation
The normal wiper system function positions are as follows:
The manual low speed and manual high speed wiper modes are continuous wiper operations as selected via the wiper switch.
Automatic Modes of Operation
The rain sensing windshield wiper system function positions are as follows:
Automatic low speed and automatic high speed wiper modes are continuous wiper operations that are controlled by the outside moisture sensor. Automatic low and high speed operation is utilized when the amount of precipitation on the windshield exceeds the
automatic delay or low threshold.
Wiper Inhibit Relay (STS-V Only)
The purpose of the wiper inhibit relay is to disable the wiper system when the hood is ajar. If the hood is in the full open position it can crash with the wiper arm if the wiper is in a non parked position.
The wiper inhibit relay, controlled by the rear integration module (RIM), is positioned between the WPR SW fuse and the windshield wiper/washer switch. Accessory voltage from the WPR fuse is applied to the relay with the ignition in the ACC or RUN positions.
The RIM monitors the voltage input of the hood open switch signal circuit and the hood open closed switch signal circuit to determine hood position. When the RIM senses that the hood is closed, it pulls the wiper inhibit relay control circuit low energizing
the relay. With the relay energized, accessory voltage from the WPR SW fuse is applied to the windshield wiper switch allowing for wiper/washer operation.
Moisture Sensitive Wipers
The outside moisture sensor monitors moisture accumulation on the windshield and uses a windshield wiper/washer switch status input to provide wipe commands to the windshield wiper/washer module. The DELAY positions on the wiper/washer switch are used
to activate the AUTOMATIC rain sensing operating mode. They are also used to adjust the level of sensitivity to moisture accumulation, which determines the dwell time for commanding a wiper motor wipe cycle.
Battery positive voltage is supplied to the outside moisture sensor through the accessory voltage circuit and RAIN SSR fuse located in the underhood fuse block. The sensor is grounded through the ground circuit and G402. Whenever the ignition is in the
run or accessory positions, the windshield wiper/washer module sends the wiper/washer switch status using a pulse width modulation (PWM) signal through the moisture sensor signal 1 circuit to the outside moisture sensor. When a wipe cycle is needed, the
moisture sensor sends a PWM voltage signal through the moisture sensor signal 2 circuit back to the wiper/washer module requesting the wiper operation.
The outside moisture sensor uses the moisture sensor signal 2 circuit to command wiper motor wipe cycles and to confirm the moisture sensor signal 1 is being received. If at anytime communication between the moisture sensor and wiper/washer
module is lost, the wiper/washer module will default to the inputs from the windshield wiper/washer switch in the delay positions to operate the wiper motor at continuous variable delay intervals.
Power and Grounds
Accessory voltage is supplied to the windshield wiper/washer module from the WPR MOD fuse located in the underhood fuse block. This voltage allows the wiper/washer system to operate only when the ignition switch is in the Accessory or On positions. The
module is grounded through the module ground circuit and G101.
Accessory voltage is supplied to the windshield wiper/washer switch from the WPR SW Fuse located in the underhood fuse block.
Wiper/Washer System Operation
The windshield wiper/washer module is part of the windshield wiper motor cover and controls wiper motor operation. The accessory voltage supplied to the windshield wiper motor assembly is used to operate the wiper motor in all modes. The windshield wiper
motor is a 2 speed motor and is operated at low speed in all modes except HIGH. When the wiper/washer switch is activated, battery voltage is applied through the switch contacts, a series of resistors, and through the wiper switch signal circuits to the
wiper/washer module. The voltage level of these signal circuits determine the windshield wiper/washer modes of operation. The following is a list of wiper/washer modes of operation:
| • | Manual Low Speed:
When the wiper/washer switch is in the LOW position, battery voltage is applied through a 24K ohm resistor and the windshield wiper switch signal 2 circuit to the module. Battery voltage is also
applied through the windshield wiper switch signal 1 circuit to the module. The reduced voltage from the wiper switch signal 2 circuit and voltage from the wiper switch signal 1 circuit indicates the manual low request. In response to these
signals, the wiper/washer module applies voltage to its internal wiper motor LOW speed terminal and the wiper motor runs in the manual LOW speed mode. |
| • | MIST:
Windshield wiper/washer system MIST operation is identical to LOW operation, as described above, except that the MIST switch is a press and release type. When the wiper switch is moved to the MIST position and released,
low speed wiper motor operation is started and will continue until 1 cycle is complete. If the wiper switch is moved to the MIST position and held, the windshield wiper motor will operate in the LOW mode until the switch is released. |
| • | DELAY:
Windshield wiper DELAY operation is also a low speed wiper motor function, but with a variable delay interval between the wiper motor cycles. The DELAY interval is controlled through a series of resistors within the
wiper/washer switch. During DELAY wiper operation the wiper switch signal 2 circuit is at the same voltage level used for LOW speed operation, but the wiper switch signal 1 circuit voltage is reduced through the DELAY resistors. The windshield
wiper/washer module uses a capacitor that is fed by the wiper switch signal 1 circuit to determine the frequency of the low speed wiper motor cycles. When the wiper switch signal 1 circuit is at a high voltage level as in the LOW switch position,
the higher voltage charges the capacitor fast, causing a delayed, but continuous LOW speed wiper motor operation. The DELAY switch position indicating the longest interval between wiper motor cycles, is the switch position with the highest resistance, resulting
in low voltage on the wiper switch signal 1 circuit. This low voltage charges the capacitor slowly, causing a long delay interval between wiper motor cycles. As the DELAY switch is turned to positions indicating more frequent wiper cycles, the resistance
through the wiper/washer switch is reduced and the wiper switch signal 1 circuit voltage increases. When the wiper switch signal 1 circuit voltage increases the capacitor charges faster and the delay interval between wiper motor cycles decreases. |
| • | Manual HIGH Speed:
When the wiper switch is placed in the HIGH position, battery voltage is applied through the switch contacts and the wiper switch signal 1 circuit, wiper switch signal 2 circuit, and the
high speed signal circuit to the wiper/washer module. During HIGH speed wiper operation, the wiper switch signal 1 and signal 2 circuits are at the LOW speed signal voltages, but, the LOW speed signal circuit inputs to the wiper/washer module are
overridden by the active HIGH speed signal circuit. In response to this signal, the wiper/washer module applies voltage to its internal wiper motor high speed terminal and the wiper motor runs in the manual high speed mode. |
| • | WASH:
The outside moisture sensor monitors the WASH switch to determine if the wash function is selected. When active, the moisture sensor uses this information to ignore the wash water input to the algorithm. During windshield
wiper/washer system WASH operation, the wiper/washer module controls the operation of both, the wiper motor and the windshield washer pump. |
| | When the WASH switch is pressed, battery voltage is applied through the switch contacts and the windshield
wiper/washer switch signal 2 circuit to the wiper/washer module indicating the wash command. The wiper/washer module then applies battery voltage to its internal wiper motor low speed terminal and the windshield washer pump control circuit for a minimum
of 3.5 seconds or as long as the WASH command is active, followed by approximately 6 seconds of wiper motor operation. |
| • | PARK or OFF:
Windshield wiper motor park operation is controlled by the wiper/washer module using an input from the PARK switch within the wiper motor assembly. When the windshield wiper/washer switch is turned to the OFF
position while the wiper motor is somewhere in mid-cycle, the wiper/washer module will continue to operate the wiper motor until the wipers reach the PARK position. |
| • | Automatic Delay:
The wipers are normally in the PARK position. The moisture sensor determines the dewell time appropriate for the amount of precipitation on the windshield after considering the wiper switch SENSITIVITY setting.
When moisture accumulation indicates a wipe is needed, the moisture sensor signals the wiper/washer module to clear the precipitation from the windshield. For all automatic delay operations the outside moisture sensor commands the wipers to operate in LOW speed
for one wipe. |
| • | Automatic Low:
Automatic LOW speed operation is utilized when the amount of precipitation on the windshield exceeds the automatic delay threshold. With a steady amount of precipitation on the windshield, the algorithm written
for this threshold will prevent cycling between automatic delay and automatic LOW speed operation. |
| • | Automatic High:
Automatic HIGH speed operation is utilized when the amount of precipitation on the windshield exceeds the automatic low threshold. With a steady amount of precipitation on the windshield, the algorithm written
for this threshold will prevent cycling between automatic LOW and automatic HIGH speed operation. |
Heated Washer Nozzles
The purpose of the heated washer nozzles is to prevent nozzle freeze-up in cold weather. With the ignition in the ON position, battery positive voltage is applied to both washer nozzles from the 10 A WASH NOZ fuse located in the underhood fuse block.
The washer nozzles are permanently grounded to G101. They are in operation at all times when the ignition is in the ON position, nothing else controls their operation.
Check Washer Fluid Message
The CHECK WASHER FLUID message is controlled by the instrument panel module (IPM) using an input from the washer fluid level switch. With the ignition is in the ON position, the IPM applies ignition voltage through an internal resistor and the windshield
washer fluid level signal circuit to the windshield washer fluid level switch. The IPM then monitors this voltage to determine the washer fluid level. With the washer fluid above a determined level, the washer fluid level switch is open and the IPM detects voltage
on the signal circuit. When the washer fluid reaches the point where the driver should be informed that the washer fluid is low, the washer fluid level switch closes. When the washer fluid level switch is closed, the washer fluid level signal circuit is pulled
low and the IPM displays the CHECK WASHER FLUID message on the driver information center (DIC). In order to prevent the CHECK WASHER FLUID message from being displayed while sloshing is occurring in the washer fluid container, the IPM is programed with a 1 minute
delay before changing states of the CHECK WASHER FLUID message during an ignition cycle.
