Ford Explorer: Wipers and Washers / Description and Operation - Wipers and Washers - System Operation and Component Description

System Operation

System Diagram

Network Message Chart

  SCCM Network Input Messages

  BCM Network Input Messages

Windshield Wipers

The wiper relay is energized when the ignition is on and provides voltage to the windshield wiper motor and the rain sensor.

The SCCM monitors the wiper/washer switch inputs and sends the wiper/washer switch data to the windshield wiper motor through a LIN circuit.

Based on the input, the windshield wiper motor activates the appropriate wash, low, high and intermittent or rain sense modes. The logic of the wiper operation is contained within the windshield wiper motor.

When the wiper/washer switch is in the high speed setting, the windshield wiper motor also receives a ground signal directly from the SCCM, bypassing the logic within the windshield wiper motor module. This fail-safe circuit makes sure the windshield wipers function in high speed mode in the event of a LIN communication failure.

Mist Wipe

When the mist wipe function is activated, the SCCM sends the request to the driver side windshield wiper motor over the LIN to perform a single wipe of the windshield. The windshield wipers operate for as long as the mist wipe function is active.

Windshield Washer

When the wiper/washer switch is activated, the SCCM sends the washer request to the windshield wiper motor over the LIN. The windshield wash relay is internal to the windshield wiper motor. When the windshield wiper motor activates the windshield wash relay, voltage is provided to the washer pump, directing washer fluid to the windshield. If equipped with a front camera, washer solvent is also directed to the front camera lens when the washer pump is active. When the switch is released, the windshield wiper motors will continue to activate for 3 additional wipes and then turn off.

Ground for the washer pump is provided through the rear window washer relay located within the BCM-C.

Courtesy Wipe

If the wiper/washer switch is off, an additional wipe occurs to clear any remaining fluid after a wash cycle has been commanded and completed.

Intermittent Wipers

When the wiper/washer switch is in an intermittent setting, the windshield wiper motors activate at timed intervals. The lower the setting, the longer the interval between wipes.

Speed Dependent Wipers

When the wiper/washer switch is in any intermittent setting except the lowest setting, the speed dependent feature increases the frequency of wiping as the vehicle speed increases to compensate for the extra moisture that accumulates on the windshield.

The SCCM receives the vehicle speed from the PCM. The SCCM then sends the vehicle speed data to the driver side windshield wiper motor through the LIN.

Rain Sensitive Wipers (if equipped)

When equipped, the rain sensitive wiper feature replaces the intermittent wiper feature. The rain sensitive feature is active when the wiper/washer switch is in any of the 6 auto/intermittent sensitivity settings. The setting closest to OFF is the least sensitive to moisture, the highest setting being the most sensitive to moisture.

The rain sensor sends data through the LIN to the windshield wiper motor. Based on the data received from the rain sensor and the auto/intermittent setting from the wiper/washer switch, the system automatically activates and adjusts the wiper speed and frequency when moisture is detected on the windshield.

If a fault is detected with the rain sensitive feature, the windshield wipers change to a default intermittent mode. The timing of the wipers correspond to a standard intermittent setting based on the auto/intermittent sensitivity setting on the wiper/washer switch.

Wiper Activated Exterior Lamps

The BCM turns the exterior lamps on within 10 seconds of the windshield wipers being activated by the wiper/washer switch when the headlamp switch is in the AUTO position. Approximately 30 seconds after the windshield wipers turn off, the BCM turns the exterior lamps off.

If equipped with rain sensitive wipers and the headlamp switch is in the AUTO position, the BCM turns the exterior lamps on when the rain sensitive wipers are activated by moisture detected on the windshield when the headlamp switch is in the AUTO position. Shortly after the rain sensitive wipers are deactivated (moisture no longer detected on the windshield), the BCM turns the exterior lamps off.

Rear Window Wiper

When the wiper/washer switch is in the INT 1 or INT 2 (continuous wipe) position, the SCCM sends the request to the windshield wiper motor through the LIN. When the request is received, the windshield wiper motor momentarily supplies ground to the rear window wiper motor, activating the motor. The position of the wiper/washer switch determines how many times per minute the windshield wiper motor provides ground to activate the rear window wiper motor.

The rear window wiper motor is self-parking.

Rear Window Washer

When the rear window washer switch is activated, the SCCM sends the request to the windshield wiper motor through the LIN. The windshield wiper motor energizes the rear washer relay (located in the BCM-C) and activates the rear window wiper motor. When the windshield wiper motor activates the rear window wash relay, voltage is provided to the washer pump, directing washer fluid to the rear window. If equipped with a rear camera, washer solvent is also directed to the rear camera lens when the washer pump is active.When the switch is released, the rear window wiper motor continues to operate for 3 additional wipes and then turns off.

Ground for the washer pump is provided through the windshield washer relay within the windshield wiper motor.

System Diagram - Heated Wiper Park (if equipped)

Network Message Chart

  FCIM Network Input Messages

Heated Wiper Park (if equipped)

The heated wiper park feature operates in conjunction with the heated windshield operation. When the heated windshield function is activated (using voice command, the touchscreen, or when the MAX defrost button is pressed on the FCIM) and the ambient air temperature is below 32° F (0° C ), the FCIM activates the heated windshield relays and the heated wiper park relay by providing ground to the relay coils. The heated wiper park relay then provides voltage to the heated wiper park grid in the windshield.

The FCIM deactivates the heated windshield relays and the heated wiper park relay when any one of the following conditions are met:

• The MAX defrost button is pressed when the feature is active.
• The ignition state changes to OFF.
• A predetermined timer completes.
• Battery voltage has dropped below a specified threshold (load management strategy).

Component Description

Wiper/Washer Switch

The wiper/washer switch is mounted directly to the SCCM. The windshield wiper/washer inputs to the SCCM are:

• Mist wipe (without police package)
• Windshield wash
• Off
• AUTO 1/INT 1
• AUTO 2/INT 2
• AUTO 3/INT 3
• AUTO 4/INT 4
• AUTO 5/INT 5
• AUTO 6/INT 6
• Low
• High

The rear wiper/washer inputs to the SCCM are:

• Off
• INT 1
• INT 2 (continuous wipe)
• Rear window wash

Windshield Wiper Motor

The windshield wiper motor is a smart motor that recieves mode requests from the SCCM through a LIN. The windshield wiper motor continuously monitors the wiper/washer switch inputs from the SCCM and the rain sensor (if equipped), when the ignition is on. Based on the wiper/washer switch inputs from the SCCM, the windshield wiper motor activates to achieve the requested mode.

The windshield wiper motor is mounted to the wiper and linkage assembly.

Washer Pump

The washer pump is controlled by the windshield wiper motor. The front and rear washer system share the same washer reservoir and a bi-directional washer pump. The washer pump delivers washer fluid to the windshield when the windshield wiper motor activates the windshield washer relay (internal to the windshield wiper motor), which provides voltage to the washer pump. Ground for the washer pump is provided through the rear washer relay (located in the BCM-C). When activated, the washer pump delivers washer fluid to the windshield.

When the windshield wiper motor energizes the rear washer relay, the rear washer relay provides voltage to the washer pump. Ground for the washer pump is provided through the windshield washer relay (internal to the windshield wiper motor). When activated, the pump delivers washer fluid to the rear window.

Rain Sensor

The rain sensor uses an infrared beam to optically sense water on the windshield. The intensity of the reflected beam is measured and compared to the intensity of the transmitted beam. If there is water on the surface of the windshield, the beam distorts, reducing the intensity of the beam. If the beam is not reflected completely, it is interpreted as rain on the windshield and the windshield wipers are activated.

A gel-type lens is integral to the rain sensor and acts as the interface between the rain sensor and the windshield. If the lens is missing or damaged, the rain sensing wipers may become inoperative and the sensor must be replaced.

Rear Wiper Motor

The rear window wiper motor contains an integrated relay and a single speed motor. When the windshield wiper motor momentarily energizes the integrated relay within the rear wiper motor, the rear window wiper activates. The integrated relay is used to continue the rear window wipe and park the wiper motor.

Heated Wiper Park (if equipped)

The heated wiper park grid is embedded in the windshield glass in the location of the windshield wiper blade park position. If damaged, the heated wiper park grid cannot be serviced separately from the windshield, a new windshield must be installed.