Land Rover Defender: Wipers and Washers - Operation

WINDSHIELD WIPERS

The windshield wiper system has the following functionality:

• Flick wipe
• Slow wipe
• Fast wipe
• Windshield wash and wipe
• Automatic wipe.

Flick wipe

Flick wipe is activated when the driver moves the windshield wiper control switch to the single wipe position. The BCM / GWM detects a message through the LIN. Then the BCM/ GWM energizes the wiper ON/OFF relay in the EJB to supply power to the windshield wiper motor. The windshield wiper motor operates at fast speed. When the windshield wiper control switch is released from the flick wipe position, the windshield wiper motor operates at slow speed. The wipers operate for a minimum of 1 full cycle before the relay is de-energized.

Slow wipe

When the driver moves the windshield wiper control switch to the slow wipe position, the BCM/ GWM detects a LIN message. The BCM/ GWM energizes the wiper ON/OFF relay in the EJB to supply power to the windshield wiper motor. The BCM/ GWM also transmits the LIN message to the windshield wiper motor to operate at slow wiping speed. The windshield wiper motor operates at slow speed until 1 of the following:

• Fast speed is selected.
• The wiper ON/OFF relay is de-energized, removing the voltage to the windshield wiper motor.

Fast wipe

When the driver moves the windshield wiper control switch to the fast wipe position, the BCM/ GWM detects a LIN message. The BCM/ GWM energizes the wiper ON/OFF relay in the EJB to supply voltage to the windshield wiper motor. The BCM/ GWM also transmits the LIN message to the windshield wiper motor to operate at fast wiping speed.

The windshield wiper motor operates at fast speed until 1 of the following:

• Slow speed is selected.
• The wiper ON/OFF relay is de-energized, removing the voltage to the windshield wiper motor.

Wash and wipe

Moving the windshield wiper control switch towards the operator selects front wash/wipe. The position is non-latching and the windshield washer pump is operated for as long as the switch is active. When the switch is only momentarily operated, only the washer pump operates. When the switch is activated for more than 250 ms, the windshield wiper motor begins to move.

The BCM/ GWM monitors the windshield wiper control switch operation. After the switch is released, the BCM/ GWM allows a number of full wipe cycles to clear the windshield. The number of full wipe cycles is dependent on headlamp wash operation.

Automatic wipe

When the windshield wiper control switch is in the 'AUTO' position, the BCM/ GWM detects and monitors the LIN message received from the rain/light sensor. The wiping speed varies depending on the vehicle speed and the moisture level detected by the rain/light sensor. The BCM/ GWM receives vehicle speed signals from the Anti-Lock Brake System Control Module (ABS) on the FlexRay.

The rain/light sensor sensitivity can be adjusted by turning the rotary switch on the windshield wiper control switch to the required position. The selected setting communicates on the LIN to the BCM/ GWM.

The intermittent function can be selected through the Touch Screen (FCDIM) to disable the autowipers function. The intermittent delay period is adjustable using the rotary switch on the windshield wiper control switch. The delay period is also subject to vehicle speed, with the selected delay period decreasing with an increase in road speed. The windshield wiper motor changes the wiping speed based on the information from the BCM/ GWM and the rain/light sensor.

Winter wiper park mode

The winter wiper park function allows the wipers to park in a higher position to lift the blades from the windshield for these reasons:

• So that the wipers do not contact the hood when you lift them off the windshield.
• So that you can clear snow from the cowl panel area.
• To allow heat from the defroster remove ice from the wiper blades.

The wipers move to the winter park position when in Power Mode 4 (accessory (vehicle unlocked and Smart Key present) ). The wipers remain in the winter park position until 1 of the following occurs:

• The vehicle speed is more than 8 km/h (5 mph).
• The wipers are operated.

The winter wiper park function is enabled or disabled through the FCDIM.

Wiper service position

The wiper service position allows the windshield wipers to be parked in a position to allow easy access to the wiper blades for replacement.

NOTE: The smart key must remain in the vehicle when the windshield wipers are in the service position.

To set the service mode to ON, do this:

1. Set the windshield wiper control switch OFF and in Power Mode 4 (accessory (vehicle unlocked and Smart Key present) ) or lower.
2. Set the windshield wiper control switch OFF and in Power Mode 6 (ignition ON) or higher.
3. Set the windshield wiper control switch OFF and in Power Mode 4 (accessory (vehicle unlocked and Smart Key present) ) or lower.
4. Move the windshield wiper control switch to the flick position when in Power Mode 6 (ignition ON) or higher.
5. The windshield wipers move to the service position.

The wipers remain in service position until in Power Mode 4 (accessory (vehicle unlocked and Smart Key present) ) or lower where they return to park position.

Vehicles with keyless entry require the smart key to be left in the vehicle. The purpose is to make sure that the vehicle remains in Power Mode 6 (ignition ON) or higher while replacing windshield wiper blades.

To return the windshield wipers to the normal park position, do this:

1. Turn the ignition switch in Power Mode 4 (accessory (vehicle unlocked and Smart Key present) ) or lower.
2. The windshield wipers return to the park position.

RAIN/LIGHT SENSOR

A = CLEAN AND DRY WINDSHIELD: B = WET AND DIRTY WINDSHIELD.

1. Windshield outer surface
2. Optical element
3. Transmitter diodes (100% light transmitted)
4. Rain/light sensor assembly
5. Receiver diodes (100% light received)
6. Water droplets or water film
7. Receiver diodes (less than 100% light received)
8. Lost light

The rain/light sensor contains a number of transmitter and receiver diodes which emit and receive infrared light. By comparing the received light signal against the known transmitted light signal, the rain/light sensor can determine the amount of water.

The autowipers are activated when the windshield wiper control switch is moved to the 'AUTO' position. The sensitivity of the rain/light sensor can be adjusted by rotating the rotary switch on the windshield wiper control switch. Clockwise rotation increases sensitivity, while counter clockwise adjustment decreases sensitivity. An increase in sensitivity adjustment results in a flick wipe.

The rain/light sensor feature can be selected through the FCDIM.

The software within the rain/light sensor can compensate the following:

• Short-term effects - For example dirt or smear, caused by worn wiper blades.
• Long-term effects - For example scratches or stone chips on the windshield, in the area of the optical unit.

CAUTION: The adaption process needs to be conducted when the outer surface of the windshield is dry and clean with the ignition ON and auto selected. Successful recognition of an adaption request shall result in a wipe cycle.

When the self-adaptation is no longer possible, a recalibration routine must completed, using the Jaguar Land Rover (JLR) approved diagnostic equipment. The routine allows to reset the rain/light sensor values then the sensor can adopt to the new conditions.

TAILGATE WIPER

NOTE: The tailgate wiper does not operate when the tailgate is open and the vehicle is stationary.

When it receives a request for tailgate wiper operation, the BCM/ GWM energizes the tailgate wiper relay in the BCMB . When energized, the relay supplies voltage to the tailgate wiper motor.

The BCM/ GWM receives signals from the park switch which is integral with the tailgate wiper motor. The purpose is to make sure the wiper returns to the park position when the tailgate wiper request is canceled mid-stroke.

The BCM/ GWM also powers the tailgate wiper motor when REVERSE is selected while the windshield wiper function is active. The REVERSE signal originates in the Transmission Control Module (TCM). The TCM transmits a REVERSE signal over the FlexRay to the BCM/ GWM, which operates the tailgate wiper (when the windshield wiper function is active).

The tailgate wiper system has the following functionality:

• Tailgate wash and wipe
• Intermittent wipe
• Continuous wipe.

Tailgate wash and wipe

Press and release the right end button on the windshield wiper control switch to operate tailgate washer and wiper.

The wiper operates in a set cycle to minimize drips when the button is released. When more washer fluid is required, push and hold the button.

Intermittent wipe

When the driver rotates the windshield wiper control switch to the tailgate intermittent wipe position, the tailgate wiper operates intermittently. There is a delay between wipes related to the speed of the vehicle.

Continuous wipe

When the driver rotates the windshield wiper control switch to the tailgate continuous wipe position, the windshield wipers operate continuously.

WINDSHIELD WASHER

When the driver moves the windshield wiper control switch to the windshield wash position, the BCM/ GWM energizes the front/rear washer pump. The BCM/ GWM delays windshield wiper operation for a short period after the driver operates the windshield wiper control switch in the windshield wash position.

When these 2 steps occur:

• The windshield wiper operates in either position.
• The driver moves the windshield wiper control switch to the windshield wash position.

The BCM/ GWM energizes the front/rear washer pump, but the wiper sequence does not change.

After the washer pump stops, the BCM/ GWM operates the wipers to complete the current wipe cycle and a number of further full cycles before PARK.

TAILGATE WASHER

When the tailgate washer operation is requested, the BCM/ GWM energizes the front/rear washer pump. The front /rear washer pump operates in the opposite direction to the windshield washer operation. Reversing the polarity of the pump allows washer fluid to be directed to the tailgate washer jet rather than the windshield washer jets.

The tailgate washer jet operates for up to 10 seconds when continuously requested. When the tailgate washer switch is released, the BCM/ GWM then operates several wipe cycles to remove any residual washer fluid from the rear window.

Washer jet - Rear proximity camera

On vehicles with rear proximity camera, the washer jet for the rear proximity camera only operates when the tailgate washer activates.

HEADLAMP WASHER - IF EQUIPPED

The headlamp washers are only active when the headlamps are switched ON and in Power Mode 6 (ignition ON) or higher.

When the windshield wiper control switch is in the windshield WASH position and the headlamps are ON, the BCM/ GWM activates the headlamp washer relay. The headlamp washer relay is in the EJB which supplies power to the headlamp washer motor.

The number of headlamp washer operations in a given period is limited to preserve the washer fluid in the washer reservoir. The BCM/ GWM then suspends the headlamp wash activation for the next 10 minutes and 3 operations of the wash/wipe switch. After the 10 minute period has expired, the headlamp power washers are activated on the fourth operation of the windshield wiper control switch.

When the driver requests more than 3 windshield washes during the 10 minutes inhibit period, the BCM/ GWM does not activate the headlamp washer again until:

• The 10 minute period has expired.
• The driver requests 1 more front wash.

When the washer fluid level becomes low, the BCM/ GWM suspends headlamp washer operation to preserve the remaining washer fluid.

DIAGNOSTICS

The BCM/ GWM records any Diagnostic Trouble Code(s) (DTC)s and related data. Read the DTCs and related data with the JLR approved diagnostic equipment.

The JLR approved diagnostic equipment can read live data and activate certain components.

CONTROL DIAGRAM

CONTROL DIAGRAM - 1 OF 1

A = HARDWIRED: O = LIN: AX = FLEXRAY: BA = HIGH SPEED (HS) CONTROLLER AREA NETWORK (CAN) HUMAN MACHINE INTERFACE (HMI) SYSTEMS BUS.

1. BCM/ GWM
2. SWM
3. TCM
4. Transfer Case Control Module (TCCM)
5. ABS
6. Power Steering Control Module (PSCM)
7. IPC
8. FCDIM
9. Heated windshield washer jet (quantity 2) (if equipped)
10. Tailgate wiper motor
11. Front/rear washer pump
12. Headlamp washer pump (if equipped)
13. Windshield wiper motor
14. Ground
15. Power supply
16. Washer fluid level sensor
17. Tailgate wiper motor
18. Rain/Light sensor
19. Windshield wiper motor
20. Windshield wiper control switch

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