LR3/Disco 3
operated for more than 10 seconds, the pump will be disabled. When the switch is released, the rear wiper will complete a
further two full wipe cycles and then operate on an intermittent function until selected off.
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 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 housing's 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 and a Positive Temperature Coefficient (PTC) sensor, which regulates the temperature. The jet heater
elements are controlled by the Automatic Temperature Control Module (ATCM) and a heated washer jet relay in the BJB.
For additional information, refer to
Control Components
(412-04 )
REVERSE GEAR INPUT
The intermittent delay period (below) depends on speed dependant wipe mode being enabled or disabled.
The rear wiper also operates if reverse gear is selected and the front wipers are on. If the front wipers are operating
continuously when reverse is selected, the rear wiper will also operate continuously as long as reverse gear is engaged. If
the front wipers are operating intermittently when reverse is engaged, the rear wiper will complete one wipe cycle then
wipe intermittently.
On vehicles fitted with rain/light sensor, when reverse gear is selected while the front wipers are in intermittent mode but
the rain/light sensor indicates that the front wipers are off, the rear wiper will not operate. If the rain/light sensor
subsequently calls for a single wipe, the rear wiper will operate a single wipe cycle. If the rain/light sensor calls for a slow
or fast wipe, the rear wiper will operate continuously.
The CJB will operate the rear wiper (providing the front wipers are on) upon receipt of a reverse gear signal from the
Electronic Automatic Transmission (EAT) module on the CAN bus, via the instrument cluster. On vehicles with manual
transmission, the gear position signal is transmitted directly from the transfer box control module and picked by the CJB
as an CAN bus message, via the instrument cluster.
'TAIL GATE OPEN' DISABLE
If the rear wiper is switched on or is already running and the tail gate is opened, the rear wiper should not start to run, or
should immediately become disabled during a wipe cycle. If the tail gate is subsequently closed, the wiper will resume its
normal operation after a delay of three seconds. Should the vehicle speed input be more than 4 mph (6km/h), then the tail
gate switch will be deemed as closed.
The CJB receives the 'tail gate open' signal directly from the upper tail gate central locking motor.
FRONT AND REAR WIPER MOTOR BLOCKING PROTECTION
The wiper park signal is also used by the CJB for blocking protection of the front wiper motor. This feature protects the
motor in the event of the wiper operation being obstructed.
If the CJB does not receive a wiper park signal status change for a period of 6 seconds, when the wiper motor is active,
the CJB removes the power supply to the motor. The motor will remain disabled until either an alternative motor mode has
been selected, or the ignition has been moved to position 0 and back to position I. Should a stall condition be achieved 3
times during a single ignition position I status, then the wiper relay will remain disabled, regardless of wiper switch
positions, for 180 seconds. The CJB will not automatically switch the motor on, to prevent the risk of injury. The wiper
switch must be moved off and then on to reactivate the wiper motor. The blocking protection is active in all wiper switch
positions and can only be reset by turning the ignition off.
The rear wiper algorithm contains the same logic as mentioned above.
DIAGNOSTICS
