WIPERS AND WASHERS
84-8 DESCRIPTION AND OPERATION
Description
General
All markets have a common wiper system with headlamp powerwash as an option.
The wipers system comprises two front wipers and one rear wiper which are powered by electric motors. A washer
reservoir is located in the front left hand wheel arch and is fitted with two electric pumps. Each pump supplies washer
fluid to either the front or rear screens. On certain models, a third pump can be fitted to operate a headlamp power
wash function. Operation of the front and rear wipers and washers is controlled by the driver using switches located
on a steering column stalk and push button switches on the fascia.
Control of the wipers and washers is achieved by the following components:
lBCU.
lIDM.
lFront wiper relay.
lFront wash/ wipe switch.
lVariable delay switch.
lFront wiper motor assembly.
lFront washer pump motor.
lRear wiper relay.
lRear wiper switch.
lRear washer switch.
lRear wiper motor.
lRear washer pump motor.
Both the Body Control Unit (BCU) and the Intelligent Driver Module (IDM) control the wiper system. The BCU controls
the time delay function of the wiper system and is located below and behind the passenger glovebox. During engine
cranking the BCU prevents wiper functions. Two relays are located in the passenger compartment fusebox. The
relays control the delay operation of the front and rear wipers. The relays are an integral part of the fusebox and
cannot be renewed separately.
Power for the wiper system is supplied by the IDM, which is integral with the passenger fusebox and cannot be
renewed as a component. A serial communication link allows communication between the IDM and the BCU.
The system has diagnostic capabilities through TestBook.
Front wipers
The two front windscreen wipers are operated by a linkage assembly and an electric motor located under the plenum
grill below the windscreen. The linkage and motor assembly is handed for left and right hand drive vehicles. The motor
is an integral part of the linkage and cannot be replaced separately.
The linkage comprises a pressed steel mounting plate which provides for the attachment of a wheel box at each end.
The mounting plate is secured to the bulkhead with flanged nuts which attach to a stud plate located behind the
bulkhead. A link arm is attached to each wheel box by a short link and secured with circlips. The link arm has an
attachment hole centrally located along its length for the electric motor drive link.
The electric motor is mounted in a recess in the bulkhead below a sealed cover plate. The drive spindle of the motor
protrudes through the cover plate and is fitted with a link. The link is attached to a tapered spline on the motor spindle
and is secured with a lock washer and nut. The opposite end of the link is attached to the central attachment point on
the link arm and secured with a circlip.
Each wheel box has a taper splined shaft which allows for the attachment of the wiper arm which is secured with a
washer and nut. The shaft of each wheel box is passed through a rubber sealed aperture in the plenum. 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 blades are attached to the wiper arms with a clips that allow the blade to pivot. Each wiper blade comprises
a number of levers and yokes to which the rubber wiper is attached. 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 contribute to the even distribution of spring pressure along the blade. The
driver's side wiper blade is fitted with an aerofoil which presses the blade onto the screen at high speed. This prevents
the blade from lifting off the screen and maintains the wiping performance.
WIPERS AND WASHERS
DESCRIPTION AND OPERATION 84-13
Rear wiper motor
The DC motor contains two permanent magnets and a park switch. An earth braid attached between the motor casing
and the brush pack is utilised to minimise radio interference during wiper functions.
The rear wiper switch provides an earth signal to the BCU, which determines the delay interval, if appropriate. The
BCU then signals the IDM to activate the rear wiper motor relay, which provides power to the rear wiper motor.
To allow the rear wiper to park when the rear wiper is switched off, power flows through the park switch until a cam
in the wiper motor assembly breaks the contact of the park switch. Triggering the park switch grounds the positive
side of the wiper motor causing it to stop abruptly
Washers
The washer system comprises a reservoir, washer pumps, hoses and washer jets. The front washers are controlled
from a stalk switch on the steering column and the rear washers are operated by a non-latching pushbutton switch on
the fascia adjacent to the instrument pack.
Reservoir
The reservoir is located behind the front bumper in the inner wheel arch and has a capacity of 6.0 litres (12.5 US pints).
A filler neck tube is connected to the reservoir with a seal and extends into the engine compartment on the front left
hand side. The filler neck tube contains a removable filter to prevent particle contamination and a yellow float to show
reservoir contents. The washer filler neck tube is sealed with a cap which is coloured blue for identification.
Two electric washer pumps are located on the rear face of the reservoir and supply washer fluid to the front
windscreen and the tail door window. Each pump is sealed to the reservoir with a rubber sealing grommet.
On vehicles with headlamp powerwash fitted, a third pump is fitted with a sealing grommet to the front face of the
reservoir.
The reservoir and filler neck tube are manufactured from moulded opaque nylon. The reservoir has moulded lugs for
attachment to the vehicle body. A bracket is attached to the top of the filler neck tube and locates in a hole in the body
to secure the top of the tube.
Front screen washer jets
Two washer jets for the front windscreen are fitted to the top surface of the bonnet and held in place with plastic clips.
Each washer jet is connected via a hose to an in-line valve. The in-line valve prevents the washer fluid draining back
to the reservoir and ensures that the washers operate immediately the washer pump is operated. From each in-line
valve the washers are connected via a short hose to a 'T' connector. From the 'T' connector a single hose connects
to the outlet of the front washer pump. Each jet has two jets which can be adjusted to allow full fluid coverage of the
windscreen.
