Description

Description

General
The wipers and washers system is controlled by the Body Control Unit (BCU) on receipt of requests made by the driver or the rain 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 one rear wiper arms and blades
- Two front washer jets and one rear washer jet (incorporated with rear wiper arm)
- A washer reservoir and three pumps
- A wash/wipe control column switch.

Other items are added to enhance the wiper system:
- Heated front washer jets
- Headlamp wash/wipe system
- A rain sensor for automatic wiper control.

The wiper system can be optionally equipped with a rain sensor. 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 four wiper stages of operation and four intermittent wiper delay periods. The four 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 wiper 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. Refer to Body Control Unit section for further details of 'power down under load'. Diagnostic information for the wiper system is available and can be retrieved using TestBook/T4.

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 one position selects intermittent front wiper operation. The rotary potentiometer on the stalk selects one of four delay periods. When a rain sensor is incorporated into the system, the intermittent position also initiates wiper operation controlled by the rain sensor. The sensitivity of the rain sensor can be adjusted by rotating the rotary potentiometer to one of the four positions. Moving the switch up one 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 three full cycles before stopping. When headlamp wash/wipe is fitted, the headlamp washers and wipers will operate if programmed wash/wipe is selected and the headlamps are on. The wash/wipe 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 one 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 five full cycle with three 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 three connections on the BCU. The BCU 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 two battery voltage feeds to the motor. 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 throu9h 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 ECU behind the battery. The relay is a tan colour for identification.

The motor has an internal track which signals the BCU 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 BCU receives the park position signal from the motor, the BCU 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 three 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 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 drivers side blade is fitted with an aerofoil which pressures 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, two washer jets and hoses.

The plastic, moulded reservoir is located in the LH wheel arch, behind the liner and has a capacity of 8.8 pints (5 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 three recessed holes on its rear face which provide location for the front, rear 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 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 in side the reservoir, into which the sensor is fitted. The sensor has two 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 two 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 LCM which displays the low fluid level message in the instrument pack.

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 two 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 two 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 six 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 condition.

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 Sensor







The rain 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 sensor unit attaches to the optical unit via four 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 retaning clips must be withdrawn to facilitate sensor removal.

The sensor provides information to the BCU, 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 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.

Rain Sensor Functionality







The rain 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 four 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 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 BCU.

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 sensor and uses ambient temperature K bus signals from the instrument pack to keep the optical unit clear of frost or condensation.

A light sensor is incorporated into the sensor and is used to increase the sensitivity of the sensor when light levels are low. This feature counteracts the effects of rain on the windscreen affecting the drivers vision during night time driving.

Rear Wiper
The rear wiper system comprises:
- Wiper motor and control module assembly
- Rear washer pump
- Wiper arm and blade.

Wiper Motor







The rear wiper and washers operation is controlled by the control module which is located with the rear wiper motor. The rear wiper operation is remote from the BCU 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 three 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 two plug sockets which accept two 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 and also a power input from the passenger compartment fusebox.

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 two, adjustable ball jets, which direct washer fluid onto the tal door window. The cap, when installed, connects with the hollow motor spindle through which the washer fluid flows to the jets.

Headlamp Wipers







The headlamp wiper assembly is located below each headlamp. The assemblies are handed and therefore are not interchangeable. Each assembly is located on a bracket which is secured to the front panel and the headlamp. The motor is secured to the bracket with two bolts.

The headlamp wiper operation is controlled by the BCU via a headlamp wiper relay. The relay is located behind the fascia. The relay is attached to the air suspension ECU mounting bracket, above the passenger compartment fusebox and can be identified by its black colour.

A 90° connector at the rear of the motor allows for the attachment of the washer fluid hose from the headlamp washer pump. The washer fluid is directed through the centre of the motor drive spindle and supplies a washer jet in the spindle cover.

The motor drives a gearbox which drives the wiper blade across the headlamp in an arc. The motor spindle protrudes through a finisher below the headlamp. A tapered spine provides positive location for the wiper arm which is secured to the spindle by a nut.

The wiper arm attachment hole has tapered splines which mate with the splines on the motor spindle. 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 headlamp lens.

A plastic cap, located on the arm pivot point, covers the spindle attachment nut. The cap also contain, an adjustable ball jet which directs washer fluid onto the headlamp lens. The cap when installed connects and seals onto the hollow motor spindle, through which the washer fluid flows to the jets.

The wiper blade is attached to the wiper arm with a clip that allows the blade to pivot. The blade comprises two yokes to which the rubber wiper blade is attached. The yokes ensure that the pressure applied by the arm tension spring is distributed evenly along the full length of the blade.