WIPERS AND WASHERS (Description): DESCRIPTION AND OPERATION

WIPERS AND WASHERS

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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:

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BCU.

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IDM.

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Front wiper relay.

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Front wash/ wipe switch.

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Variable delay switch.

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Front wiper motor assembly.

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Front washer pump motor.

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Rear wiper relay.

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Rear wiper switch.

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Rear washer switch.

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Rear wiper motor.

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Rear 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.