Discovery 2. Manual — part 303

WIPERS AND WASHERS

DESCRIPTION AND OPERATION

84-5

1 Windscreen washer jet 2 off
2 Elbow 3 off
3 In-line non-return valve
4 Tube
5 'T' connector
6 Tube
7 Connector
8 Filler neck tube
9 Filter

10 Cap
11 Bracket
12 Level float
13 Filler neck seal
14 Bolt
15 Reservoir
16 Pump sealing grommet (if fitted)
17 Powerwash pump (if fitted)

18 Clip
19 Tube
20 Screw 2 off
21 Powerwash jet 2 off
22 Clip 4 off
23 Tube
24 'T' connector
25 Tube
26 Nut 2 off
27 Pump sealing grommet 2 off
28 Rear washer pump
29 Front windscreen washer pump
30 Elbow 2 off
31 Tube - front windscreen
32 Tube - rear tail door window
33 Non-return valve

WIPERS AND WASHERS

84-6

DESCRIPTION AND OPERATION

Wipers and washers block diagram

WIPERS AND WASHERS

DESCRIPTION AND OPERATION

84-7

1 BCU
2 IDM
3 Front wiper relay
4 Front wash / wipe switch
5 Front wiper motor assembly
6 Front washer pump motor
7 Variable delay switch
8 Rear wiper relay
9 Rear wiper switch

10 Rear washer switch
11 Rear wiper motor
12 Rear washer pump motor
13 Headlamp power wash relay
14 Headlamp power wash pump motor

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:

l

BCU.

l

IDM.

l

Front wiper relay.

l

Front wash/ wipe switch.

l

Variable delay switch.

l

Front wiper motor assembly.

l

Front washer pump motor.

l

Rear wiper relay.

l

Rear wiper switch.

l

Rear washer switch.

l

Rear wiper motor.

l

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.