Wiper and Washer Systems: Description and Operation
FRONT WIPER/WASHER SYSTEMDESCRIPTION
The front wiper and washer system includes the following major components:
- Front Washer Nozzle - Two fluidic front washer nozzles are secured by integral latch features to dedicated openings in the hood panel near the base of the windshield. Each nozzle includes an integral front washer system check valve.
- Front Washer Plumbing - The plumbing for the washer system consists of rubber hoses and molded plastic fittings. The plumbing is routed to the engine compartment from the washer reservoir. The front washer hose is routed along the left side of the engine compartment to the dash panel, then across the underside of the hood panel to the washer nozzles.
- Front Wiper Arms & Blades - The two front wiper arms are secured with nuts to the threaded ends of the two wiper pivot shafts, which extend through the cowl plenum cover/grille panel located near the base of the windshield. The two front wiper blades are secured to the two wiper arms with an integral latch, and are parked on the glass near the bottom of the windshield when the front wiper system is not in operation.
- Front Wiper Module - The wiper pivot shafts are the only visible components of the front wiper module. The remainder of the module is concealed within the cowl plenum beneath the cowl plenum cover/grille panel. The wiper module includes the wiper module bracket, three rubber-isolated wiper module mounts, the wiper motor, the wiper motor crank arm, the two wiper drive links and the two wiper pivots.
- Right Multi-Function Switch - The right (wiper) multi-function switch is secured to and directly connected to the Steering Control Module (SCM), on the steering column just below the steering wheel. Only the switch control stalk extending from the right side of the steering column is visible, while the remainder of the switch is concealed beneath the steering column shrouds. The right multi-function switch is dedicated to providing all of the driver controls for both the front and rear wiper and washer systems.
- Steering Control Module - The Steering Control Module (SCM) is secured to the top of the steering column, just below the steering wheel and is completely concealed beneath the steering column shrouds.
- Totally Integrated Power Module - The Totally Integrated Power Module (TIPM) is located in the engine compartment, near the battery.
- Washer Pump/Motor - The reversible electric washer pump/motor unit is located in a dedicated hole on the lower, outboard side of the washer reservoir, on the passenger side, under the cowl plenum. This single washer pump/motor provides washer fluid to either the front or rear washer system plumbing, depending upon the direction of the pump motor rotation.
- Washer Reservoir - The washer reservoir is concealed between the left inner fender shield and the left outer fender panel, ahead of the left front wheel house splash shield. The filler neck and cap are the only visible components of the reservoir and, are accessed from the left front corner of the engine compartment.
REAR WIPER/WASHER SYSTEM
The rear wiper and washer system includes the following major components:
- Rear Washer Nozzle - The fluidic rear washer nozzle is integral to the Center High-Mounted Stop Lamp (CHMSL) located on the liftgate outer panel above the liftgate flip-up glass. The rear washer nozzle includes an integral check valve.
- Rear Washer Plumbing - The plumbing for the rear washer system consists of rubber hoses and molded plastic fittings. The plumbing is routed along the left side of the engine compartment from the washer reservoir, through the dash into the passenger compartment, up the left cowl side and A-pillar where it is connected to a hose integral to the headliner that runs from the A-pillar to the rear washer nozzle on the upper liftgate header.
- Rear Wiper Arm & Blade - The single rear wiper arm is secured by a nut directly to the rear wiper motor output shaft, which extends through the center of the liftgate outer panel near the base of the liftgate flip-up glass. The rear wiper blade is secured to the rear wiper arm with an integral latch, and is parked off of the glass when the rear wiper system is not in operation.
- Rear Wiper Module - The rear wiper module includes the module bracket, two rubber-isolated wiper module mounts and the rear wiper motor. The wiper motor output shaft is the only visible component of the rear wiper module. The remainder of the module is concealed within the liftgate.
- Right Multi-Function Switch - The right (wiper) multi-function switch is secured to and directly connected to the Steering Control Module (SCM), on the steering column just below the steering wheel. Only the switch control stalk extending from the right side of the steering column is visible, while the remainder of the switch is concealed beneath the steering column shrouds. The right multi-function switch is dedicated to providing all of the driver controls for both the front and rear wiper and washer systems.
- Steering Control Module - The Steering Control Module (SCM) is secured to the top of the steering column, just below the steering wheel and is completely concealed beneath the steering column shrouds.
- Totally Integrated Power Module - The Totally Integrated Power Module (TIPM) is located in the engine compartment, near the battery.
- Washer Reservoir - The rear washer system shares a single reservoir and reversible pump with the front washer system, but has its own dedicated plumbing. The washer reservoir is concealed between the left inner fender shield and the left outer fender panel, ahead of the left front wheel house splash shield. The filler neck and cap are the only visible components of the reservoir and, are accessed from the left front corner of the engine compartment.
OPERATION
FRONT WIPER/WASHER SYSTEM
The wiper and washer system is designed to provide the vehicle operator with a convenient, safe, and reliable means of maintaining visibility through the windshield glass. The various components of this system are designed to convert electrical energy produced by the vehicle electrical system into the mechanical action of the wiper blades to wipe the outside surface of the glass, as well as into the hydraulic action of the washer system to apply washer fluid stored in an on-board reservoir to the area of the glass to be wiped. When combined, these components provide the means to effectively maintain clear visibility for the vehicle operator by removing excess accumulations of rain, snow, bugs, mud, or other minor debris from the outside windshield glass surface that might be encountered while driving the vehicle under numerous types of inclement operating conditions.
The vehicle operator initiates all wiper and washer system functions with the control knob (1) on the end of the control stalk (2) of the multi-function switch that extends from the left side of the steering column, just below the steering wheel. Rotating the control knob on the end of the control stalk, selects the Off, Delay, Low, or High wiper system operating modes. In the Delay mode, the control knob also allows the vehicle operator to select from one of five intermittent wipe Delay intervals. Depressing the control knob towards the steering column actuates the momentary washer system switch, which selects the Wash, Wipe-After-Wash Modes depending upon when and how long the switch is held closed.
The multi-function switch provides hard wired resistor multiplexed inputs to the ElectroMechanical Instrument Cluster (EMIC) for all of the wiper and washer system functions. The EMIC then sends electronic messages to the Totally Integrated Power Module (TIPM) over the Controller Area Network (CAN) data bus requesting the appropriate wiper and washer system operating modes.
Wiper and washer system operation are completely controlled by the instrument cluster and TIPM logic circuits, and that logic will only allow these systems to operate when the ignition switch is in the Accessory or On positions. The TIPM uses intelligent, high current, self-protected high side switches to control wiper system operation by energizing or de-energizing the wiper motor low and high speed brushes. The TIPM uses a high side driver to control the operation of the washer pump/motor unit. The multi-function switch circuitry receives a clean ground output from the instrument cluster on a multi-function switch return circuit, then provides resistor multiplexed inputs to the instrument cluster on an intermittent wipe mux circuit to indicate the selected wiper system mode and on a wash/beam select mux circuit to indicate the selected washer system mode.
The hard wired circuits and components of the wiper and washer system may be diagnosed and tested using conventional diagnostic tools and methods. However, conventional diagnostic methods may not prove conclusive in the diagnosis of the EMIC, the TIPM, or the electronic message inputs to or outputs from the EMIC or the TIPM that control the wiper and washer system operating modes. The most reliable, efficient, and accurate means to diagnose the EMIC or the TIPM inputs and outputs related to the various wiper and washer system operating modes requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.
OPERATING MODES
Following are paragraphs that briefly describe the operation of each of the wiper and washer system operating modes.
CONTINUOUS WIPE MODE
When the Low position of the control knob on the control stalk of the multi-function switch is selected the EMIC sends an electronic wiper switch low message to the TIPM, then the TIPM directs battery current to the low speed brush of the wiper motor, causing the wipers to cycle at low speed. When the High position of the control knob is selected the EMIC sends an electronic wiper switch high message to the TIPM, then the TIPM directs battery current to the high speed brush of the wiper motor, causing the wipers to cycle at high speed.
When the Off position of the multi-function switch control knob is selected, the EMIC sends an electronic wiper switch off message to the TIPM. If the wiper motor was operating at high speed, the TIPM immediately de-energizes the wiper motor high speed brush and energizes the low speed brush causing the wiper motor to return to low speed operation. Then one of two events will occurs, which depends upon the position of the wiper blades on the windshield at the moment that the control knob Off position is selected.
If the wiper blades are in the down position on the windshield when the Off position is selected, the park switch that is integral to the wiper motor is closed to ground and provides a hard wired park switch sense input to the TIPM. The TIPM then de-energizes the wiper motor low speed brush and the wiper motor ceases to operate. If the wiper blades are not in the down position on the windshield at the moment the Off position is selected, the park switch is an open circuit and the TIPM keeps the wiper low speed brush energized, which causes the wiper motor to continue running at low speed until the wiper blades are in the down position on the windshield and the park switch input to the TIPM is again closed to ground.
INTERMITTENT WIPE MODE
When the control knob on the control stalk of the multi-function switch is moved to one of the Delay interval positions the EMIC sends an electronic wiper switch delay message to the TIPM, then the TIPM electronic intermittent wipe logic circuit responds by calculating the correct length of time between wiper sweeps based upon the selected delay interval input. The TIPM monitors the changing state of the wiper motor park switch through a hard wired park switch sense input. This input allows the TIPM to determine the proper intervals at which to energize and de-energize the wiper motor low speed brush to operate the wiper motor intermittently for one low speed cycle at a time. The TIPM logic is also programmed to provide vehicle speed sensitivity to the selected intermittent wipe delay intervals. In order to provide this feature the TIPM monitors electronic vehicle speed messages from the Powertrain Control Module (PCM) and doubles the selected delay interval whenever the vehicle speed is about sixteen kilometers-per-hour (ten miles-per-hour) or less.
WASH MODE
When the control knob on the control stalk of the multi-function switch is depressed to the momentary Wash position for more than about one-half second, the EMIC sends an electronic washer switch message to the TIPM, then the TIPM directs battery current to the washer pump/motor unit. This will cause the washer pump/motor unit to be energized for as long as the Wash switch is held closed up to about thirty seconds, and to de-energize when the Wash switch is released.
When the control knob is depressed to the momentary Wash position while the wiper system is operating in one of the Delay interval positions, the washer pump/motor operation is the same. However, the TIPM also overrides the selected delay interval and operates the wiper motor in a continuous low speed mode for as long as the control knob is held depressed, then reverts to the selected delay mode interval several wipe cycles after the control knob is released. If the control knob is held depressed for more than about ten seconds, the TIPM will suspend washer pump/motor operation until the knob is released for about two seconds, then cycled back to the Wash position.
WIPE-AFTER-WASH MODE
When the control knob on the control stalk of the multi-function switch is depressed to the momentary Wash position for more than about one-half second while the wiper system is not operating, the EMIC sends an electronic washer switch message to the TIPM, then the TIPM directs battery current to the washer pump/motor unit and energizes the wiper motor low speed brush. This will cause the washer pump/motor unit to be energized and operate the wiper motor in a continuous low speed mode for as long as the Wash switch is held closed up to about ten seconds. When the control knob is released, the TIPM de-energizes the washer pump/motor unit, but allows the wiper motor to operate for several additional wipe cycles before it de-energizes the wiper motor low speed brush and parks the wiper blades near the base of the windshield.
If the control knob is held depressed for more than about ten seconds, the TIPM will suspend washer pump/motor operation until the knob is released for about two seconds, then cycled back to the Wash position; however, the wipers will continue to operate for as long as the Wash switch is held closed. The TIPM monitors the changing state of the wiper motor park switch through a hard wired wiper park switch sense circuit input. This input allows the TIPM to count the number of wipe cycles that occur after the Wash switch is released, and to determine the proper interval at which to de-energize the wiper low speed brush to complete the wipe-after-wash mode cycle.
REAR WIPER/WASHER SYSTEM
The vehicle operator initiates all rear wiper and washer system functions with the control sleeve (3) on the control stalk (1) of the right multi-function switch that extends from the right side of the steering column, just below the steering wheel. Rotating the control sleeve on the control stalk to the various detent and momentary positions selects the rear wiper and washer system operating modes. The right multi-function switch provides resistor multiplexed inputs to the left multi-function switch, the left switch then sends a message over the Local interconnect Network (LIN) data bus to the CCN, and then the CCN sends a bus message over the CAN data bus to the TIPM for all of the rear wiper and washer system functions.
The TIPM provides battery voltage and ground to operate the washer pump/motor unit and a control output to the rear wiper relay, which provides battery voltage to operate the rear wiper module. Rear wiper/washer system operation is completely controlled by the TIPM logic circuits, and that logic will only allow these systems to operate when the ignition switch is in the Accessory or On positions.
The most reliable, efficient, and accurate means to diagnose the right multi-function switch or the TIPM inputs and outputs related to the various rear wiper and washer system operating modes requires the use of a diagnostic scan tool and the appropriate diagnostic information.