Part 1
Wipers and Washers
General
The wiper and washer system is controlled by the Central Junction Box (CJB) on receipt of requests made by the driver or the rain/light sensor unit (if fitted). All wiper functions for the front and rear wipers are controlled from a multi-function wash/wipe switch assembly located on the right hand side of the steering column.
The wiper and washer system comprises:
^ Front and rear wiper motors
^ A front wiper linkage
^ Two front and one rear wiper arms and blades
^ Two front washer jets and one rear washer jet
^ A washer reservoir and pump
^ A wash/wipe control column switch.
The following optional items can be added to enhance the wiper system:
^ A rain/light sensor for automatic wiper control
^ Heated front washer jets
^ Headlamp washers
^ Low fluid level sensor (fitted to vehicles with headlamp washers).
The wiper system can be optionally equipped with a rain/light sensor. The sensor, located below the interior rear view mirror, detects raindrops on the windshield and automatically controls the operating speed of the front wipers. The column stalk switch must be in the intermittent position for rain/light sensor controlled wiper operation.
The front wiper system has five stages of operation and six intermittent delay periods.
The five wiper stages are as follows:
^ Flick wipe
^ Off
^ Intermittent
^ Normal (slow) speed continuous
^ Fast speed continuous.
Speed Control Intermittent Mode
The intermittent delay period is affected by road speed, providing the speed control intermittent wipe mode has been configured. The intermittent wiper delay periods change with the road speed and wiper sensitivity positions, with the delay decreasing as the road speed increases.
Speed Dependant Wipe Mode
When the speed dependant wipe mode has been configured, the normal continuous operation changes to intermittent operation when the vehicle has been driven above 2 mph (3km/h) and then drops below 2 mph (3km/h). The fast speed operation changes to normal operation when the vehicle has been driven above 2 mph (3km/h) and then drops below 2 mph (3km/h).
The wiper and washers operate with the ignition switch in positions I or II. Wiper functions are suspended during engine cranking to reduce battery power consumption under high load conditions.
Diagnostic information for the wiper system is available and can be retrieved using T4.
Central Junction Box (CJB)
The CJB is an integrated unit located behind the instrument panel on the passenger side of the bulkhead. The CJB contains fuses, relays and a number of microprocessors, which control the power supply and functionality of the wash/wipe system and other vehicle systems.
Inputs and Outputs
The CJB receives and sends the following wiper and washer system inputs and outputs:
Inputs
^ Intermittent front wipe switch
^ Rear wipe park switch
^ Rain/light sensor, if fitted
^ Normal (slow) speed continuous switch
^ Fast speed continuous switch
^ Flick wipe switch
^ Front shield wash switch
^ Rear shield wash switch
^ Ignition switch
^ Lighting switch
^ Low level reservoir status, via CAN
^ Vehicle speed, via CAN
^ Front wiper motor park switch
^ Reverse switch, via CAN
^ Tail gate open switch
^ Ambient temperature, via CAN
Outputs
^ Front wiper motor (normal)
^ Front wiper motor (fast)
^ Washer motors
^ Heated washer jets (if fitted)
^ Rear wiper motor relay
^ Headlamp power wash motor
Front Wiper Assembly
The front wiper assembly comprises:
^ Wiper motor and linkage assembly
^ Wiper arms and blades
^ Washer reservoir, pumps and jets.
Wiper Linkage
The wiper linkage and motor assembly are available as separate components. The wiper linkage and motor differs between LH and RH drive models.
The assembly is located below the plenum grill in the engine compartment and is secured with bushes, sleeves and bolts. The rubber bushes isolate the assembly from the body mountings.
The linkage assembly comprises a main tube, with a pivot housing at each end. The motor is attached directly to the tube. A motor crank is positively attached to the motor output shaft. Two link rods then attach to the motor crank, which transfers power directly to each pivot crank.
The motor crank converts rotary motion from the motor output shaft into linear movement of the link rods. The cranks, connected between the each link rod and pivot housing, convert the linear motion to reciprocating motion at the pivot housing. This reciprocating motion is passed to the wiper arms and blades causing the blades to wipe an arc across the windshield.
Wiper Motor
The motor assembly comprises a dc motor, which drives a gear wheel via a worm drive attached to the motor spindle. The gear wheel has a central spigot, which provides the attachment point for the motor crank.
A five-pin connector connects the motor electrically. The connector supplies two battery voltage feeds to the motor (when switched). The motor has three sets of brushes with one brush connected to ground. One feed is direct to the motor brush opposite the ground brush and operates the motor at normal (slow) speed. The second feed is connected to a motor brush, which is offset from the ground brush and operates the motor at fast speed. With the power supplied through this brush, the current flows through fewer coil windings. This results in a lower resistance to the current flow to the ground brush and gives a higher motor rotational speed.
Output control of the wiper motor is through a double contact relay. The relay is located in the Battery Junction Box (BJB).
The motor has an internal track switch, which signals the CJB when the wipers have reached the park position. The park signal is closed circuit when the wipers are in the park position. When the wipers are switched off and the CJB receives the park position signal from the motor, the CJB shorts the motor via a relay bridge circuit. This short circuit has the effect of applying a brake to the motor, giving precise positioning of the wiper blades in the park position.
Wiper Arms
The wiper arms are positively located on tapered splines on the wiper linkage spindles.
The wiper arm has a pivot point, midway between the spindle attachment and the blade. A tension spring is connected to the wiper arm on each side of the pivot point and applies pressure to maintain the wiper blade in contact with the windshield. The wiper blades are attached to the wiper arms with clips that allow the blade to pivot.
The wiper blades comprise a sprung steel curved backbone which applies pressure evenly to the windshield, to which is applied the wiping lip to the bottom surface and an aerofoil section to the top which presses the blades onto the windshield at high vehicle speeds.
Rear Wiper Assembly
The rear wiper assembly comprises:
^ Wiper motor
^ Rear washer pump
^ Rear washer jet
^ Wiper arm and blade
^ Glass sealing grommet.
Wiper Motor
Rear wiper and washer operation is controlled by the CJB, via the rear wiper relay, which is located in the LH 'D' post.
The rear wiper motor is located in the upper tailgate, behind a trim panel. The assembly is secured to the body of the upper tailgate with three M6 nuts. Bushes isolate the motor assembly from the body, which help reduce the transmission of motor operating noise to the tailgate.
The motor is located on a worm drive gearbox mechanism, which converts the rotary motion of the motor output spindle into the required arc for the rear wiper blade.
The feed hose, for the separate rear washer jet, is located at the rear of the motor spindle. The hose is connected to a 90 degrees connector allowing the washer fluid to flow through the center of the motor spindle. A Non-Return Valve (NRV) is located in the hose, near the motor, and prevents fluid returning to the reservoir.
The motor spindle is a conventional design with a taper spline location for the wiper arm and a threaded shank to secure the arm to the spindle.
Wiper Arm
The wiper arm is similar in design to the front wiper arms. The arm attachment hole has tapered splines, which mate with the splines on the wiper spindle. The arm is secured to the wiper motor spindle with a nut. The wiper arm has a pivot point, close to the spindle attachment. A tension spring is connected to the wiper arm on each side of the pivot point and applies pressure to maintain the wiper blade in contact with the windshield.
The wiper blade is attached to the wiper arm with a clip that allows the blade to pivot. The blade comprises a number of levers and yokes to, which the rubber wiper blade is attached. The levers and yokes ensure that the pressure applied by the arm tension spring is distributed evenly along the full length of the blade and also allow the blade to adjust to the curvature and contour of the windshield.
A plastic cap located on the arm pivot point, covers the spindle attachment nut.
Washer Reservoir And Pumps
The windshield washer system comprises:
Vehicles without headlamp washers:
^ A reservoir and filler neck
^ A washer pump
^ Two washer jets
^ A rear washer jet
^ Hoses
Vehicles with headlamp washers:
^ A reservoir and filler neck
^ Two washer pumps
^ A level sensor
^ Four washer jets - two windshield and two headlamp washers
^ A rear washer jet
^ Hoses
The plastic, moulded reservoir is located in the LH wheel arch, behind the liner and has a capacity of 11.08 pints (6.3 liters). It is secured to the body and front panel with bolts. A boss on the reservoir locates in a slot in the front panel and provides additional support.
The reservoir has two recessed holes on its rear face, which provide location for the combined front pump, rear pump and headlamp washer pumps. The pumps are push fitted into grommets, which seal the pumps in their locations. A hole in the top of the reservoir allows for the fitment of a flexible filler neck. The front and rear wash hoses are integrated into the harness and so follow it's routing. The headlamp washer hose comes from the bumper around the bottle to attach to the headlamp washer pump.
A hole with a grommet in the side of the reservoir provides the location for the fluid level sensor.
The low level sensor has a float, with integral magnet. The sensor has a contact, which is normally closed when the reservoir is full. When the fluid level reduces to approximately 1 liter, the magnetic float pivots down, which causes the switch contact to open. This open circuit is sensed by the instrument cluster, which displays the low fluid level message and transmits the switch status on the CAN bus.
The sensor cannot determine the precise amount of fluid in the reservoir, but can detect when the fluid level has fallen below a certain point. When the fluid level is low, the magnetic float closes the sensor contacts, completing a circuit through the sensor. This completed circuit is sensed by the instrument cluster, to which the sensor is directly connected.
The instrument cluster monitors the fluid level sensor continuously. The instrument cluster checks the fluid level sensor when the ignition is switched on to give the driver an early warning of the low fluid level.The instrument cluster then monitors the sensor value over a 25 second period when the ignition is on to prevent invalid messages due to fluid 'sloshing' in the reservoir.
When a low fluid level signal is transmitted to the high line instrument cluster, a 'WASHER FLUID LOW' message is displayed in the instrument cluster's message center. On the low line instrument cluster a low fluid level indicator is illuminated. The first display of this message, or illumination of the indicator, is accompanied by a 'chime' sound to alert the driver to the low fluid level.
Headlamp Washers
The headlamp washer assembly is located below each headlamp.
The headlamp washer operation is controlled by the CJB via a headlamp washer relay. The relay is located in the BJB.
Head Lamp Wash Only (No Wipe Function)
The headlamp washers are only active when the headlamps and ignition are switched on. If the washer reservoir fluid level becomes low, the instrument cluster sends a message, via the CAN bus, to the CJB, which suspends headlamp wash operation to preserve washer fluid in the reservoir.
With the ignition and lights on, headlamp wash is activated on the first operation of the wiper column control switch in the wash/wipe position.
The CJB monitors the operation of the wash/wipe switch and maintains a counter to restrict headlamp washer operation to every fourth operation of the wash/wipe switch in conjunction with a 10-minute timer. The timer prevents a second operation of the headlamp washers within a 10-minute period. Should the washer switch be activated for more than four programmed wipe requests during the 10-minute period, the headlamp washer will remain disabled. Only the next consecutive programmed wipe request, after the 10-minute timer has expired, will the headlamp washers be enabled. The counter and timer are reset when the ignition is switched to OFF or the light switch is turned from OFF back to ON within the same ignition cycle. When headlamp wash is active, the CJB energises the washer pump twice per cycle. The headlamp washer pump is powered for a 0.5 second period.
Rain/Light Sensor
The rain/light sensor is located at the upper edge of the windshield, behind the interior rear view mirror. The sensor is mounted on an optical unit, which is heat bonded to the inner surface of the windshield during manufacture. If damage occurs to the optical unit or the windshield, then a new windshield will be required and installation can only be performed by an authorised Land Rover dealer.
The rain sensor must be re-initialised to a new windshield, if fitted, or if transferred to another vehicle, the new rain sensor assembly will automatically re-initialise when powered-up for the first time. In order for this to occur successfully it must be fitted and connected to the optical filaments (bonded to the shield assembly).
The rain/light sensor unit attaches to the optical unit via two clips, which latch onto formed tags on the optical unit. Positive retention is achieved by two retaining clips, which force the clips onto the tags. The retaining clips must be withdrawn to facilitate sensor removal.
The sensor provides information to the CJB for the optimum wiper operation for the prevailing conditions to maintain the shield in a clear condition at all times. The rain/light sensor is an optical unit, which operates on an infrared waveband. The sensor uses the principle of the laws of reflection on interfacing surfaces between materials with differing refraction properties.