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Wipers And Washers
Wiper and Washer System Component Location
GENERAL
The wipers and washers system is controlled by the Generic Electronic Module (GEM) 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 multifunction 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 1 rear wiper arms and blades
^ Two front washer jets and 1 rear washer jet (incorporated with rear wiper arm)
^ A washer reservoir and 3 pumps
^ A wash/wipe control column switch.
Other items are added to enhance the wiper system:
^ Heated front washer jets
^ Headlamp power wash system
^ A rain/light sensor for automatic wiper and headlamp control.
The wiper system can be optionally equipped with a rain/light sensor, which controls the automatic wiper functions and also the automatic lighting functions. The sensor, located below the interior rear view mirror, detects rain drops on the windscreen and automatically operates the wipers in the intermittent mode. The column stalk switch must be in the intermittent position for rain sensor controlled wiper operation.
The front wiper system has 4 wiper stages of operation and 4 intermittent wiper delay periods. The 4 wiper stages are as follows:
^ Flick wipe
^ Intermittent
^ Normal (slow) speed continuous
^ Fast speed continuous.
The intermittent, normal and fast speeds are affected by road speed. The intermittent wiper delay periods change with the road speed, with the delay decreasing as the road speed increases. The normal continuous operation changes to intermittent operation when the vehicle is stationary. The fast speed operation changes to normal operation when the vehicle is stationary.
The wipers and washers operate with the ignition switch in positions I or II (aux or ign). 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 the Land Rover approved diagnostic system.
Wiper Control Column Switch
The wiper control column switch is located on the right hand side of the steering column and controls all front and rear wiper functions.
Moving the switch up 1 position selects intermittent front wiper operation. The rotary potentiometer on the stalk selects 1 of 6 delay periods. When a rain/light sensor is incorporated into the system, the intermittent position also initiates wiper operation controlled by the rain/light sensor. The sensitivity of the rain/light sensor can be adjusted by rotating the rotary potentiometer to 1 of the 6 positions. Moving the switch up 1 further position selects normal (slow) continuous wiper operation. Moving the switch up to the last position selects fast continuous wiper operation.
Moving the switch down selects the flick wipe function. The front wipers will operate at normal speed for as long as the flick wipe switch position is operated and will stop at the park position when the switch is released.
Moving the switch rearwards, towards the driver, selects the programmed front wash/wipe function. The windscreen washer pump will operate for as long as the switch is held. A short operation operates the pump momentarily and the wipers complete 3 full cycles before stopping. The headlamp power washers will operate if programmed wash/wipe is selected and the headlamps are on. The power wash function can also be selected by depressing the button on the end of the stalk.
Moving the switch forwards to the first switch position selects the rear wiper on. The rear wiper will complete 1 full cycle and will then operate on an intermittent function until selected off. The intermittent delay between wipes can be adjusted by selecting the wiper on, then off and then on again. Moving the switch forward to the second position selects the programmed rear wash/wipe function. The wiper completes 5 full cycles with 3 automatic, short operations of the rear washer pump. The rear wiper then operates in the rear wiper on mode until selected off.
The rear wiper also operates continuously if reverse gear is selected and the front wipers are on.
The wiper control column switch comprises 8 switch positions and the intermittent rotary control. The switch positions each complete a combination of earth paths to 3 connections on the GEM. The GEM interprets the selected combination of switches and operates the respective function accordingly.
FRONT WIPERS
The front wiper system comprises:
^ Wiper motor and linkage assembly
^ Washer reservoir and pumps
^ Wiper arms and blades.
Wiper Linkage
The wiper linkage and motor assembly are available as separate components. The wiper linkage differs between LH and RH drive models. The wiper motor is common to 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. A bracket is attached, offset along the tube length, which locates the motor assembly. A motor crank is positively attached to the motor output shaft. A link rod is connected to the motor crank and is connected at the opposite end to the RH pivot housing, via a crank. The RH link rod has a pivot attachment for the LH link rod, which is connected at its opposite end to the RH pivot housing, via a second 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 back to rotary motion of the pivot housing. This rotary motion is passed to the wiper arms and blades causing the blades to wipe an arc across the windscreen.
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.
The motor is connected electrically by a four-pin connector. The connector supplies 2 battery voltage feeds to the motor. The motor has 3 sets of brushes with 1 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 engine compartment, adjacent to the transfer box control module, behind the battery. The relay is a tan colour for identification.
The motor has an internal track, which signals the GEM when the wipers have reached the park position. The park signal is an open circuit when the wipers are in the park position. When the wipers are switched off and the GEM receives the park position signal from the motor, the GEM 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 arm is located on a curved wiper angle adjuster, which mates with the curved underside of the arm attachment. A curved slot in the arm attachment locates an adjustment shim and the 3 components are retained under compression on the spindle spline by a self-locking nut.
The wiper angle adjuster and the angle adjust shim allow the approach angle of the wiper blade to be finely adjusted to its optimum wiping angle. The adjustment allows the approach angle of the blade to be adjusted to 2° on each side of the spindle axis. This adjustment provides precise adjustment of the blade approach angle for maximum wiper performance. The wiper angle adjuster is pressed onto the spindle and requires a tool for removal. Once removed, the wiper angle adjuster must be discarded and new one fitted on re-assembly.
The wiper arm has a pivot point, midway between the spindle attachment and the blade. Two tension springs are connected to the wiper arm on each side of the pivot point and apply pressure to maintain the wiper blade in contact with the windscreen.
The wiper blades are attached to the wiper arms with clips that allow the blade to pivot. Each 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 windscreen. The driver's side blade is fitted with an aerofoil, which presses the blade onto the windscreen at high speed, improving the wiper performance.
Washer Reservoir and Pumps
The windscreen washer system comprises a reservoir, a washer pump, 2 washer jets and hoses.
The plastic, moulded reservoir is located in the LH wheel arch, behind the liner and has a capacity of 12.3 pints (7 litres). It is secured to the body and front panel with bolts and washers. A boss on the reservoir locates in a slot in the front panel and provides additional support.
The reservoir has 3 recessed holes on its rear face, which provide location for the front, rear and headlamp power 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 tube. The hose is routed into the left hand side of the engine compartment and is sealed with a rubber cap. A breather hose is fitted into an elbow on the top of the reservoir and is routed alongside the filler and secured in a clip near the filler cap in the engine compartment.
A hole in the base of the reservoir provides the location for the fluid level sensor. The hole provides access to an internal tube inside the reservoir, into which the sensor is fitted. The sensor has 2 pegs, which positively locate the sensor in the reservoir when turned through 90°.
The sensor reacts to the influence of a magnetic field. A float, with integral magnet, is located around the tube, inside the reservoir. The sensor has 2 contacts inside a glass tube, which are normally open. When the fluid level reduces, the magnetic float moves down the tube. When the magnet reaches the sensor contacts, the magnetic field closes the contacts. This completed circuit is sensed by the Light Control Module (LCM), which displays the low fluid level message in the instrument cluster.
Heated Windscreen Washer Jets
Two windscreen washer jets are located in the rear trim panel on the bonnet outer surface. The washer fluid feed hose from the front screen pump is connected to a 'Y' piece connector located between the 2 jets. Two short lengths of hose connect the jets to the 'Y' piece. Each jet contains a Non-Return Valve (NRV) to prevent washer fluid draining back to the reservoir and also to limit the amount of washer fluid, which can be forced by gravity from the jet during cornering.
Each washer jet has 2 ball nozzles, which can rotate in their housings to obtain the optimum fluid application onto the windscreen. Each washer jet contains a heater element, which prevents the fluid freezing in the nozzles in very cold conditions. The jet heater elements are controlled by the Automatic Temperature Control (ATC) system, which energises the heater elements when the ambient temperature falls below a predetermined temperature.
Wiper Blade Heating
The lower, black, portion of the windscreen contains 6 heating elements, which run from one side of the screen to the other. These elements are designed to heat the area of the windscreen where the wiper blades rest to prevent freezing in cold conditions.
The blade heating elements are controlled by the ATC system, which energises the blade heating elements when the ambient temperature falls below a predetermined temperature. The operation of the blade heating elements is activated simultaneously with the heated washer jets.
RAIN/LIGHT SENSOR
The rain/light sensor is located at the upper edge of the windscreen, behind the interior rear view mirror. The sensor is mounted on an optical unit which is heat bonded to the inner surface of the windscreen during manufacture. If damage occurs to the optical unit or the windscreen, then a new windscreen will be required and fitment can only be performed by an authorised Land Rover dealer.
The rain/light sensor unit attaches to the optical unit via 4 clips which latch onto formed tags on the optical unit. Positive retention is achieved by 2 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 GEM, via the K bus, for the optimum wiper operation for the prevailing conditions to maintain the screen 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 indices.
The sensor contains 4 transmitter and receiver diodes for increased sensitivity and also contains a light sensor for operation of the automatic headlamp function.
Rain/light Sensor Functionality
The rain/light sensor contains transmitter and receiver diodes, which transmit and receive infrared light, which is directed onto the windscreen via an optical unit. The light is directed at an angle so that the light is reflected 100% on the outside surface of the screen and is transmitted back into the optical unit. To receive a 100% reflection, the outer screen surface must be clean and dry.
The light is reflected 4 times from when it leaves the transmitter diodes to when it is picked up by the receiver diodes. If the windscreen is wet or dirty in the area of the optical unit, the clean conditions for 100% reflection means that some of the light reflected is lost. As the screen becomes dirtier or wetter, the received light is evaluated by the rain/light sensor and translated into a signal value. A micro-controller within the sensor monitors the change in signal and initiates the appropriate wipe cycle via K bus signals to the GEM.
The software can compensate for the long-term effects of scratches and stone chips in the area of the optical unit and the short term effects of dirt or smears caused by worn wiper blades. A heater element is also contained within the rain/light sensor and uses ambient temperature K bus signals from the instrument pack to keep the optical unit clear of frost or condensation.
The rain/light sensor incorporates a light guide. The light guide directs the ambient light and a proportion of the forward light (from the driving direction) to a light sensitive diode. This is used for the rain sensor sensitivity in low ambient light levels and is also used to control the automatic headlamp function.
Intermittent (single wipe), continuous slow, and continuous fast front wiper operations are controlled by the rain/light sensor when enabled.
REAR WIPER
The rear wiper system comprises:
^ Wiper motor and control module assembly
^ Rear washer pump
^ Wiper arm and blade. Wiper Motor
Wiper Motor
The rear wiper and washer operation is controlled by a control module, which is located with the rear wiper motor. The rear wiper operation is remote from the GEM control of the front wiper systems.
The rear wiper motor and control module assembly is located in the upper tail door, behind a trim panel. The assembly is secured to a bracket on the upper tail door with 3, Torx head screws. Rubber bushes isolate the motor assembly from the bracket, which help reduce the transmission of motor operating noise to the tail door.
The assembly comprises the motor, mounting bracket and control module. 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 control module is integral with the motor and has 2 plug sockets, which accept 2 multiplugs from the harness. One multiplug has 2.5 mm diameter wires. Two of the wires supply permanent battery feed and ground connections for the motor and control module. The third wire in this plug supplies a power supply to the rear washer pump. The second multiplug has 0.35 mm diameter wires and carries signal data from the wash/wipe control stalk switch and the LCM. There is also a power input from the CJB.
The rear washer feed hose is located at the rear of the motor spindle. The hose is connected to a 90° connector allowing the washer fluid to flow through the centre of the motor spindle. An 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 spring washer and 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 windscreen.
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 windscreen.
A plastic cap located on the arm pivot point, covers the spindle attachment nut. The cap also contains 2, adjustable ball jets, which direct washer fluid onto the tail door window. The cap, when installed, connects with the hollow motor spindle, through which the washer fluid flows to the jets.