Scheme 16
Scheme 17
Scheme 18
WINDSCREEN WIPERS
Two front windscreen wipers are operated by a single electric motor. The motor and a link assembly are located below the plenum grill at the base of the windscreen.
The link assembly is handed for left and right hand drive vehicles. All other wiper components remain common to both versions. The component descriptions and operation are the same for both left and right hand drive.
The parallel coupled link assembly comprises a curved galvanized tube which has a cast wheel box pushed into each end of the tube and crimped for retention. A galvanized link arm is attached to a lever at the base of each wheel box.
Each link is attached by a spherical bearing which is permanently attached to the lever and the link. The opposite end of each link also has a spherical bearing, which are both attached to a spigot which in turn is attached to a lever. The lever has a splined bore and mates with a splined shaft from the motor. A spring washer and nut secure the lever to the shaft.
Each wheel box comprises a cast housing, through which a splined shaft is located on bearings. The outer end of each shaft has splines which provide positive location for the wiper arms. The link assembly is a sealed unit and is not serviceable. The motor is attached to the link assembly with three bolts. The motor can operate at two speeds for fast and slow wiper operation. The motor is a DC motor with permanent magnets. The central shaft of the motor is fitted with a worm drive which in turn rotates a gear connected to the splined drive shaft.
A wiper arm is located on the splined shaft of each wheel box and secured with a nut. The wiper arm attachment to the splined shaft has a pivot to which the remainder of the arm is attached. The two parts of the arm are connected by a spring which controls the pressure of the blade on the screen to a predetermined amount.
Each wiper blade is attached to its wiper arm with a clip that allows the blade to pivot. Each wiper blade comprises a number of levers and yokes to which the rubber wiper is fitted. The levers and yokes ensure that the pressure applied by the arm spring is distributed evenly along the full length of the blade. The rubber wiper is held in the yokes by a pair of stainless steel strips, which also distribute the spring pressure evenly. The driver's side wiper blade is fitted with an aerofoil, which presses the wiper blade onto the windscreen at high speed. This prevents the wiper blade from lifting off the screen and maintains the wiping performance.
REAR SCREEN WIPER
The rear screen wiper is attached to a splined shaft which is driven by an electric motor via an eccentric drive mechanism.
The motor is a single speed dc motor with permanent magnets. The motor shaft is fitted with a worm drive which rotates a gear wheel. The gear wheel has an offset spigot to which an eccentric cam is fitted which can rotate through 180° in each direction. A coil spring is located around the cam and operates as a simple friction clutch to enable the cam to be rotated when the motor is driven in reverse. A connecting link is attached to the cam and drives two gears located in a link. The connecting link converts the rotary motion of the gear wheel into linear movement of the link. The linear movement is converted back into rotary movement of the splined shaft which moves the wiper arm in an arc in two directions across the rear screen.
The wiper motor has the ability to park the wiper arm off the rear screen when the wiper is selected off. When the motor is operating to wipe the rear screen, the motor shaft is rotating in a clockwise direction. When the rear screen wiper is selected off, the Central Control Unit (CCU) allows the wiper arm to reach the vertical position on the screen. A microswitch, actuated by a slip ring on the underside of the gear wheel, signals that the wiper arm has reached this position. The CCU then reverses the polarity of the supply to the motor which causes the motor shaft to rotate in an anti-clockwise direction.
When the motor changes direction, the eccentric cam is rotated through 180° which effectively lengthens the linear movement of the connecting link. This causes the wiper arm to sweep across the screen to its park position. The longer linear movement of the connecting link, causes the wiper arm to rotate further than during normal wiping, parking the wiper arm and blade off screen. A second slip ring operated microswitch, on the underside of the gear wheel, signals the CCU that the wiper arm has reached the off screen position and the CCU removes the supply to the rear screen wiper motor.
The wiper arm is located on the splined shaft from the motor and secured with a nut. The wiper arm attachment to the splined shaft has a pivot to which the remainder of the arm is attached. The two parts of the arm are connected by a spring which controls the pressure of the blade on the screen to a predetermined amount.
The wiper blade is pushed onto the wiper arm which has a clip-on feature that allows the blade to pivot. The wiper blade comprises a lever, two yokes and a plastic strip. The rubber wiper is fitted to the plastic strip and held in the yokes. The lever, yokes and plastic strip ensure that pressure applied by the arm spring is distributed evenly along the length of the blade.
Scheme 19
WINDSCREEN WASHERS
The windscreen washers consist of two washer jets located on the top surface of the bonnet. Each washer jet contains two adjustable outlets which can be moved to obtain the correct coverage of the windscreen. The two washer jets are connected in series to a flexible pipe which is routed in the electrical harness to a washer reservoir. The reservoir is located inside the RH front wheel arch behind the wheel arch liner. A non-return valve is located in the feed pipe to the windscreen washer jets to prevent washer fluid siphoning back to the reservoir.
The reservoir is moulded from plastic and has a capacity of approximately 4.0 litres (1.0 US gallon). The reservoir has two ports which allow for the attachment of two washer pumps. The flexible pipe from the windscreen washer jets is connected to the forward of the two electric washer pumps. The reservoir has a filler tube which protrudes into the engine compartment. The tube is sealed by a removable cap. A filter is located in the neck of the filler tube and prevents the ingress of particulate matter when replenishing the reservoir. The filter can be removed for cleaning.
REAR SCREEN WASHER
The rear washer uses the same reservoir as the windscreen washers. A second electric washer pump is fitted to the reservoir and supplies washer fluid, via a pipe located in the wiring harness, to a single washer jet which is fitted in the rear wiper arm. The washer jet has four outlets which direct washer fluid to each side of the wiper blade. A non-return valve is located in the feed pipe to the rear screen washer jet to prevent washer fluid siphoning back to the reservoir.
GENERAL
The wipers and washers operate only while the ignition switch is in position II. Operation of the rear screen wiper and washer is prevented or discontinued if the tail door opens, the tail door window is lowered or, on 3 door models, the roof is opened (soft back) or removed (hard back).
The wash/wipe stalk, located on the RH side of the steering column, and the CCU control the operation of the wipers. Intermittent wipe, slow speed and fast speed are selected using a rotary wiper control switch on the stalk. A flick wipe function can be selected using the stalk. The CCU is responsible for the operation of the intermittent wipe facility and the park facility when the wipers are turned off.
Intermittent Wipe
When intermittent wipe is selected, the wipers operate at slow speed with a delay between wipes. A five position rotary potentiometer, inboard of the wiper control switch, varies the time delay of the intermittent wipe function. The CCU monitors the resistance through the rotary potentiometer and adjusts the time delay to suit the position selected.
The following table details the resistance at each rotary potentiometer position and the corresponding time delays
| Switch Position | Switch Resistance, ohm | Delay, Seconds |
|---|---|---|
| 1 | 0 | 3 +/- 1 |
| 2 | 1600 +/- 80 | 5 +/- 1 |
| 3 | 3200 +/- 160 | 8 +/- 2 |
| 4 | 4800 +/- 240 | 12 +/- 2 |
| 5 | 6400 +/- 320 | 17 +/- 3 |
| Default | Open circuit | 8 +/- 2 |
WINDSCREEN WIPERS SPECIFICATION
Slow and Fast Speeds
Slow and fast speed operation is achieved by three brushes in the motor. One brush is the common earth. The slow speed is initiated by a brush positioned 180° to the common brush. The fast speed is initiated by a brush positioned at approximately 45° to the common brush. The fast speed operates by the brushes transferring direct current to a smaller portion of the armature coils, which causes the armature to rotate faster, but with a lower torque than the slow speed.
Flick Wipe
The wipers perform a single wipe at fast speed if the wash/wipe stalk is momentarily moved down. If the stalk is held down the wipers operate at fast speed until the stalk is released.
The rear screen wiper is controlled from a latching push switch, located on the RH side of the instrument pack cowl, and the CCU. The wiper operates only while the tail door window is closed and, on 3 door models, the roof is closed (soft back) or on (hard back).
The CCU operates the wiper motor via a dual, forward/reverse relay installed above the RH rear suspension turret. The forward relay is energised when the wiper is operating in intermittent and continuous modes. The reverse relay is energised to reverse the rotational direction of the motor to activate the off-screen park function.
Intermittent
When the rear window wiper switch is selected on, the CCU initially operates the wiper continuously for approximately 6 seconds (3 or 4 wipes) and then changes to intermittent operation with a fixed delay of five seconds between wipes.
Continuous
When reverse gear is engaged while the rear screen wiper is on, the CCU changes the wiper to continuous operation until reverse gear is disengaged, then reverts to intermittent operation again. If reverse gear is engaged while the rear screen wiper is off, but the windscreen wipers are on, the CCU also operates the rear screen wiper continuously, until reverse gear is disengaged or the windscreen wipers are selected off.
Off-screen Park
When the rear screen wiper is selected off, the CCU waits for the next signal from the wiper vertical microswitch in the wiper motor, then de-energises the forward relay and energises the reverse relay. The reverse relay operates the motor in the opposite direction, which lengthens the stroke of the wiper arm. When the wiper arm reaches the off-screen position, the CCU receives a signal from the off-screen park microswitch in the wiper motor and de-energises the reverse relay to stop the wiper.
Off-screen Park Monitoring
In order to monitor the off-screen park function, the CCU invokes a 10 second timer each time intermittent or continuous operation of the rear screen wiper is deselected (by either the control switch on the instrument pack cowl or the CCU). If, within the 10 seconds, a signal is received from both the vertical and the off-screen park microswitches in the wiper motor, the CCU determines that the system is serviceable and continues operation as normal. If, within the 10 seconds, a signal is not received from both microswitches, the CCU determines there is a fault with one of the microswitches or the motor circuit and de-energises the forward and reverse wiper relays to prevent further operation. Since a faulty wiper could stop at any position on the tail door window, to prevent damage to the wiper or window after a fault is detected, the CCU also inhibits operation of the tail door window, with the following exceptions
- Clear of seal/seal engagement window movement when the tail door is opened/closed.
- Automatic window retraction when the roof is removed/opened.
- Window calibration using the vehicle key in the tail door lock.
When the fault has been corrected, tail door window operation returns to normal after the CCU has detected the two microswitch inputs from the rear screen wiper motor again.
The windscreen washers are operated by pulling on the wash/wipe stalk located on the RH side of the steering column. Operation of the windscreen washers can also operate the windscreen wipers in a programmed wash/wipe mode.
When the wash/wipe stalk is pulled, the washers operate immediately and stop immediately the stalk is released. When the stalk is held on for more than 0.6 second, the CCU enters the programmed wash/wipe mode and, if the windscreen wipers are selected to intermittent operation or off, operates them at slow speed. If the windscreen wipers are already selected to slow or fast speed, they remain at the selected speed. When the stalk is released with the CCU in the wash/wipe mode, if the windscreen wipers are selected to intermittent operation or off, the wipers operate at slow speed for a further 2 seconds (3 or 4 wipes) and then revert to intermittent operation or park, as applicable.
The rear washer is controlled by a non-latching push switch, located on the RH side of the instrument pack cowl, and the CCU. Pressing the rear washer switch operates the washer until the switch is released. When the washer switch is pressed, the CCU also operates the rear screen wiper in a programmed wash/wipe mode. While the switch is pressed, the CCU operates the wiper continuously. When the switch is released the CCU operates the wiper continuously for a further six seconds (3 or 4 wipes) and then parks the wiper or reverts to the previous operating mode.