Operation
OPERATION
FRONT WIPER/WASHER SYSTEM
All front wiper and washer system functions are initiated with the control knob on the end of the multi-function switch control stalk that extends from the left side of the steering column, just behind the steering wheel. Rotating the control knob on the end of the control stalk, selects the Off, Intermittent, Auto (on models equipped with automatic wipers), Low, or High front wiper system operating modes. In the Intermittent mode, the control knob also allows the vehicle operator to select from one of six intermittent wipe intervals. In the Auto mode, the control knob also allows the vehicle operator to select from one of six automatic wiper sensitivity levels. Pressing in on the end of the control stalk momentarily activates the Mist Wipe. Pressing it in all the way will activate the windshield washers. In the Auto mode, as you increase the sensitivity of the wipers (less delay between wipes), the result will be a corresponding acknowledgment wipe to let you know you made an adjustment to the system. The multi-function switch provides hard wired resistor multiplexed inputs to the Steering Column Control Module (SCCM), for all of the wiper and washer system functions. The SCCM then sends electronic messages to the Front Control Module (FCM) over the Controller Area Network (CAN) data bus requesting the appropriate front wiper and washer system operating modes.
All the front wiper and washer system operation is controlled by the FCM logic circuits, and that logic will only allow these systems to operate when the ignition switch is in the Accessory or On positions. Battery current is directed from a B(+) fuse in the Integrated Power Module (IPM) to the wiper on/off relay and the wiper high/low relay in the PDC through a fused B(+) circuit. The FCM uses low side drivers to control wiper system operation by energizing or de-energizing the wiper high/low and wiper on/off relays. The FCM uses both high side and low side drivers to control the operation of the washer pump/motor unit. The multi-function switch circuitry receives a clean ground output from the SCCM on a multi-function switch return circuit, then provides resistor multiplexed inputs to the SCCM 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.
AUTOMATIC WIPE MODE
In models equipped with the automatic wiper feature, the internal circuitry of both the multi-function switch, the rain sensor, and the CCN work in concert to provide an automatic wiper mode with five sensitivity selections. When selected, this switch position will automatically operate the front wipers at the designated sensitivity setting and maintain visibility through the windshield glass at that predetermined sensitivity setting.
With automatic wipers, when the control knob on the control stalk of the multi-function switch is moved to one of the six Auto sensitivity positions, the SCCM sends an electronic message to the Rain Sensor over the Controller Area Network (CAN) data bus network indicating the selected position. The sensor monitors an area within the wipe pattern of the windshield glass for the accumulation of moisture. Based upon internal programming and the selected sensitivity level, when sufficient moisture has accumulated the rain sensor sends the appropriate electronic wipe command messages to the FCM over the CAN data bus and the FCM operates the front wiper system accordingly.
As the sensitivity level is set higher, the rain sensor is more sensitive to moisture accumulation and will send wipe commands more frequently. The SCCM logic is also programmed to provide an immediate wipe cycle each time the control knob on the multi-function switch is moved from a non-automatic wipe position to one of the six Auto sensitivity positions, and another immediate wipe cycle each time the control knob is moved from a lower Auto sensitivity position to a higher Auto sensitivity position.
CONTINUOUS WIPE MODE
When the Low position of the control knob on the control stalk of the multi-function switch is selected, the SCCM sends an electronic wiper switch low message to the FCM, then the FCM energizes the wiper on/off relay. This directs battery current through the normally open contacts of the energized wiper on/off relay and the normally closed contacts of the de-energized wiper high/low relay 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 SCCM sends an electronic wiper switch high message to the FCM, then the FCM energizes both the wiper on/off relay and the wiper high/low relay. This directs battery current through the normally open contacts of the energized wiper on/off relay and the normally open contacts of the energized wiper high/low relay 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 SCCM sends an electronic wiper switch off message to the FCM. If the wiper motor was operating at high speed, the FCM immediately de-energizes the wiper high/low relay causing the wiper motor to return to low speed operation. Then one of two events will occur. The event that occurs 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 FCM. The FCM then de-energizes the wiper on/off relay 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 FCM keeps the wiper on/off relay 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 FCM is again closed to ground.
HEADLAMPS ON WITH WIPERS MODE
The CCN provides an automatic headlamps on with wipers feature for models equipped automatic headlamps. This is a customer programmable feature. If this feature is enabled, the headlamps will turn on automatically whenever the windshield wipers are turned on; and, if the headlamps were turned on automatically when the wipers were turned on, they will also turn off automatically when the wipers are turned off. If this feature is enabled, when the automatic wiper mode is selected the headlamps will turn on automatically only after the wipers complete a minimum of five automatic wipe cycles within about sixty seconds, and they will turn off automatically after four minutes elapse without any wipe cycles.
INTERMITTENT WIPE MODE
When the control knob on the control stalk of the multi-function switch is moved to one of the Intermittent interval positions the SCCM sends an electronic wiper switch delay message to the FCM, then the FCM electronic intermittent wipe logic circuit responds by calculating the correct length of time between wiper sweeps based upon the selected delay interval input. The FCM monitors the changing state of the wiper motor park switch through a hard wired park switch sense input. This input allows the FCM to determine the proper intervals at which to energize and de-energize the wiper on/off relay to operate the wiper motor intermittently for one low speed cycle at a time.
The FCM logic is also programmed to provide vehicle speed sensitivity to the selected intermittent wipe delay intervals. In order to provide this feature the FCM monitors electronic vehicle speed messages from the Powertrain Control Module (PCM) and doubles the selected delay interval whenever the vehicle speed is approximately sixteen kilometers-per-hour (ten miles-per-hour) or less.
PULSE WIPE MODE
When the control knob on the control stalk of the multi-function switch is depressed to the momentary pulse wipe position for less than about one-half second, the SCCM sends an electronic switch message to the FCM, then the FCM energizes the wiper on/off relay for one complete wipe cycle. The FCM de-energizes the relay when the state of the park switch sense changes to ground, parking the wiper blades near the base of the windshield.
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 SCCM sends an electronic washer switch message to the FCM, then the FCM directs battery current and ground 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 ten seconds, and to de-energize when the front 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 intermittent interval positions, the washer pump/motor operation is the same. However, the FCM also energizes the wiper on/off relay to override the selected delay interval and operate the wiper motor in a continuous low speed mode for as long as the control knob is held depressed, then de-energizes the relay and 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 FCM will suspend washer pump/motor operation until the knob is released. then cycled back to the Wash position if so desired.
The headlamp washer system (if equipped) utilizes a separate high pressure pump that is attached to the windshield washer reservoir. The headlamp washer pump feeds nozzles that are mounted in the front fascia of the vehicle. The nozzle bodies spray the headlamps with high pressure washer solvent when the system is activated.
To activate the headlamp washers, turn ON the headlamps and then press the windshield washer control knob. This will operate the windshield washers and direct two timed high pressure sprays onto the headlamp lens.
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 instrument cluster sends an electronic washer switch message to the FCM, then the FCM directs battery current and ground to the washer pump/motor unit and energizes the wiper on/off relay. 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 FCM 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 on/off relay and parks the wiper blades near the base of the windshield.
If the control knob is held depressed for more than about thirty seconds, the FCM will suspend washer pump/motor operation until the knob is released, 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 FCM monitors the changing state of the wiper motor park switch through a hard wired wiper park switch sense circuit input. This input allows the FCM 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 on/off relay to complete the wipe-after-wash mode cycle.
REAR WIPER/WASHER SYSTEM - WAGON ONLY
NOTE: FOR ALL MARKETS: The Passenger Airbag Disable (PAD) lamp is no longer functional. It is still present, but will not illuminate at any time.
All rear wiper and washer system functions are initiated with the rear wiper and washer switch in the instrument panel switch pod located on the instrument panel center bezel, just above the radio and below the A/C outlets. Pushing the left side of the wiper/washer switch selects the rear wiper system operating mode (intermittent). it has fixed 10 seconds delay between wipe (not adjustable). indicator at bottom of the WIPE graphic will light up when the wipe switch is ON and goes away when the wipe is OFF. Depressing the momentary contact switch activates the rear washer system. When a rear wiper or washer mode is selected, the circuitry within the instrument panel switch pod sends an electronic rear wiper/washer switch status message over the Controller Area Network (CAN) data bus to the ElectroMechanical Instrument Cluster (EMIC) also referred to as the Cab Compartment Node (CCN). The CCN then sends electronic messages to the Front Control Module (FCM) over the CAN data bus requesting the appropriate rear wiper and washer system operating modes.
INTERMITTENT WIPE MODE
When the rear wiper switch is pressed to the left, the instrument cluster sends an electronic wiper switch message to the FCM, then the FCM electronic wipe logic circuit responds by selecting a predetermined length of time between wiper sweeps.
WASH MODE
When the rear washer control switch is depressed to the right in the momentary Wash position, the instrument cluster sends an electronic washer switch message to the FCM, then the FCM directs battery current and ground to the washer pump/motor. This will cause the washer pump/motor to be energized for as long as the Wash switch is held closed up to about ten seconds, and to de-energize when the rear wiper/washer switch is released.
WIPE-AFTER-WASH MODE
When the rear washer switch is released from the momentary Wash position, the instrument cluster sends an electronic washer switch message to the FCM. The FCM de-energizes the washer pump/motor, but allows the rear wiper motor to operate for several wipe cycles before it de-energizes the rear wiper relay.
OFF MODE
When the Off position of the rear wiper switch is selected, one of three events is possible. The event that will occur depends upon the position of the wiper blade on the liftgate glass and the mode the wiper motor is operating under at the moment that the Off position is selected. If the wiper blade is in the down position on the glass and the rear wiper system is operating in the intermittent cycle mode when the Off position is selected, the park switch is open and the FCM de-energizes the rear wiper relay control coil causing the rear wiper motor to cease to operate.
If the wiper blade is not in the down position on the glass and is operating in the intermittent cycle mode when the Off position is selected, the park switch is closed to ground and the FCM keeps the rear wiper relay control coil energized to operate the rear wiper motor until the rear wiper blade is in the down position on the glass and the park switch input is an open circuit.
The third event occurs with the rear wiper operating in the wipe-after-wash mode when the Off position is selected, in which case the FCM will continue to run the wiper motor until the completion of two wipes after wash before the rear wiper blade is parked. The FCM will also run the rear wiper motor to park the rear wiper blade if the ignition switch is turned to the Off position while the rear wiper system is still operating.