Description
Wipers and Washers
NOTE:
A = Hardwired; N = Medium speed CAN (controller area network) bus; O = LIN (local interconnect network) bus
WINDSHIELD WIPERS
Operation of the wipers and washers is controlled by the CJB (central junction box) in response to driver inputs from the wiper control switch and signals from the rain/light sensor. The instrument cluster monitors the condition of the wiper/washer control switch and transmits driver requests to the CJB (central junction box) over the medium speed CAN (controller area network) bus.
The wiper control switch is connected via hardwired connections to the instrument cluster. The instrument cluster outputs on 4 wires a reference voltage to the wash/wipe switch, the auto wiper switch, the wiper switch and the flick wipe switch. All the switches are connected to the instrument cluster on a common ground. Each switch function is connected to ground via a resistor or series of resistors and the instrument cluster monitors the ground signal and determines which function has been selected. The instrument cluster then outputs the appropriate message on the medium speed CAN (controller area network) bus to the CJB (central junction box) which responds to the requested wiper function. The CJB (central junction box) then activates the appropriate function either directly or via relays in the EJB (engine junction box) for the wipers and headlamp powerwashers.
Speed Dependent Mode
When the wipers are operating, a vehicle speed signal received by the CJB (central junction box) on the high speed CAN (controller area network) bus is used to operate a speed dependent mode. If the wipers are in fast wipe and the vehicle speed decreases to below 2 km/h (1.2 mph), the wipers will reduce to the normal wipe speed. When the vehicle speed increases to above 8 km/h (5 mph) the fast wiper speed selection is restored. If slow speed is selected and the vehicle speed drops below 2km/h (1.2 mph), the wipers will operate in the intermittent mode. When the vehicle speed increases to above 8 km/h (5 mph) the slow wiper speed selection is restored - this feature is configurable by the dealer using the approved Jaguar diagnostic system.
Wiper Motor
The wiper motor is controlled by the CJB (central junction box). The CJB (central junction box) is connected to a wiper motor normal/fast relay in the EJB (engine junction box) on 2 wires. The CJB (central junction box) is also connected to a wiper run/park relay, also located in the EJB (engine junction box).
Driver requests are received by the CJB (central junction box) which energizes the wiper motor normal/fast relay in the appropriate mode (normal or fast wipe) and also energizes the run/park relay in the run mode by providing a ground for the relay coils. When wiper operation is deselected by the driver, the CJB (central junction box) monitors a park switch which is integral with the wiper motor. On receipt of a signal from the park switch, the CJB (central junction box) de-energizes the run/park relay, removing the power supply through the normal/fast relay, stopping the wipers in the park position on the windshield.
The wiper motor is a DC (direct current) motor which drives a gear wheel via a worm drive attached to the motor spindle. The motor has 3 sets of brushes with one brush connected to ground. When the normal/fast relay is energized in the normal position, a power feed is supplied to the brush directly opposite the ground brush and operates the motor at slow speed. When the relay is energized in the fast position, a power feed is connected to the second motor brush, which is offset from the ground brush and operates the motor at the fast speed. With power supplied through the offset brush, the current flows through fewer motor coil windings. This results in a lower resistance to current flow to the ground brush and produces a higher motor rotational speed.
WINDSHIELD WASHERS
The windshield washers are controlled by the CJB (central junction box). A driver request for washer operation, via the wiper control switch, is passed to the instrument cluster on the LIN (local interconnect network) bus. The instrument cluster passes the message to the CJB (central junction box) on the medium speed CAN (controller area network) bus.
The CJB (central junction box) energizes the windshield washer pump during the up stroke of the first 2 wash/wipe cycles. This ensures that wiper fluid is pushed to the sides of the windshield and eliminates the trail of fluid which can occur if the fluid is pushed to the bottom of the windshield. The wipers will continue for 3 more cycles, followed after a delay of 4 seconds, by a single dry wipe.
NOTE:
The dry wipe feature is configurable using an approved Jaguar diagnostic system.
The operation of the washer pump on the wiper up stroke only is configurable using an approved Jaguar diagnostic system.
The washer button can be pressed and held and the wipers will operate continuously for up to 10 seconds. After this period when the button is released, the wipers will continue for 3 more cycles, followed after a delay, by a single dry wipe. After this period washing will be inhibited, the wipers will continue for 3 more cycles, followed after a delay, by a single dry wipe. Reactivating the switch will recommence the wash/wipe cycle.
RESERVOIR LEVEL SWITCH
The level switch is connected directly to the CJB (central junction box). The switch is operated by a float which closes contacts within the switch when the fluid level falls to below the switch level. When the contacts are closed a ground path is completed from the CJB (central junction box) through the switch. This is sensed by the CJB (central junction box) which issues a message to the instrument cluster which displays a low fluid level warning.
HEADLAMP POWERWASHERS
The headlamp powerwash is activated when the driver requests windshield washer operation. The CJB (central junction box) receives the driver request via a CAN (controller area network) bus message from the instrument cluster. The CJB (central junction box) then checks for an exterior lights active signal and that a low washer fluid level signal is not present.
The CJB (central junction box) outputs a control voltage to a headlamp powerwash pump relay located in the EJB (engine junction box). The relay is energized by the CJB (central junction box) for a pre-determined period to allow the headlamp telescopic washers to operate.
The CJB (central junction box) monitors the driver washer requests and only operates the headlamp powerwash on every fourth request for windshield washer operation, provided that 10 minutes have elapsed since the last headlamp powerwash operation. The powerwash sequence is reset when the headlamps or the ignition is switched off.
NOTE:
If a low fluid reservoir level is present the CJB (central junction box) prohibits headlamp powerwash.
RAIN/LIGHT SENSOR
On receiving a request for automatic windshield wiper operation, the CJB (central junction box) interprets LIN (local interconnect network) bus messages received from the rain sensor. The rain sensor provides LIN (local interconnect network) bus messages with values ranging from 0 to 7.
A signal value of 0 is interpreted by the CJB (central junction box) as the windshield is dry. A signal value from 1 to 5 is interpreted by the CJB (central junction box) as a small amount of water hitting the windshield. In this instance, the CJB (central junction box) initiates a slow wipe. A signal value of 7 is interpreted by the CJB (central junction box) as a large amount of water hitting the windshield. In this instance, the CJB (central junction box) initiates a fast wipe.
NOTE:
The CJB (central junction box) will only change a fast wipe routine to a slow wipe routine if the rain sensor value is lower than 7.
NOTE:
A = Clean and dry windshield; B = Wet and dirty windshield
WINDSHIELD WIPER MOTOR AND LINKAGE
NOTE:
LHD (left-hand drive) wiper linkage shown
The wiper linkage and motor assembly differs between LHD (left-hand drive) and RHD (right-hand drive) models. The wiper linkage and motor assembly is not available as separate service components. If the wiper linkage and motor assembly is replaced, it is important that alignment is made to marks on the windshield and the fixings are tightened in the correct order.
The wiper linkage and motor assembly is attached to the vehicle body with screws and washers at each end. The screws are located in rubber bushes in the linkage assembly which isolate the linkage from the vehicle body. A rubber grommet is located behind the motor and engages on a spigot on the vehicle body to locate the linkage.
The linkage assembly comprises a main tube with a pivot housing located at each end. The motor assembly is attached to the tube by a clamp plate and 4 screws. The motor output shaft is fitted with a crank. A link rod is connected to the motor crank and is connected at the opposite end to the LH (left-hand) pivot housing via a crank. The LH (left-hand) pivot housing crank is fitted with a second link rod which is connected directly to the crank on the RH (right-hand) pivot housing.
The motor crank converts rotary motion from the motor output shaft into linear movement of the link rods. The cranks connected to each pivot housing, convert the linear motion of the link rods back to rotary motion of the pivot housings. This rotary motion is passed to the wiper arms and blades causing the blades to wipe an arc across the windshield.
Each wiper arm is located on a taper spline on the respective pivot housing. A nut is screwed on the end of the pivot housing shaft and positively secures the wiper arm on the taper spline.
The wiper blades are attached to the wiper arms with a quick release fittings. The blades are of the flat blade type. These blades have an integral spring along their full length which curves the blade to match the windshield and provides even blade to windshield contact pressure along the entire length of the blade.
WASHER RESERVOIR
NOTE:
Type 'B' washer reservoir shown
The washer reservoir is located in the RH (right-hand) wheel arch. The reservoir is a plastic moulding and is secured in the wheel arch with 2 screws and washers and a scrivet. A level sensor is located in the reservoir and is connected to the CJB (central junction box). The reservoir is fitted with a washer pump which supplies pressurized washer fluid to the windshield washer jets mounted on the wiper arms.
A vehicle fitted with optional headlamp washers is fitted with a larger reservoir and an additional pump for the headlamp washers. The larger reservoir is identifiable by a letter 'B' moulded on the casing and has a capacity of 5.5 liters. Reservoirs moulded with the letter 'A' are for use on vehicles with windshield washers only and have a capacity of 4.4 liters.
A filler cap is located at the top of the reservoir and is accessible from the engine compartment.
The pumps are located in rubber sealing grommets in holes in the reservoir and secured with clips. The pump fluid hoses have quick release connectors which mate with the pumps. The fluid level sensor is a push fit into a sealing grommet in one side of the reservoir body.
HEADLAMP POWERWASHERS (if fitted)
On vehicles with headlamp powerwash, each headlamp assembly is fitted with a headlamp powerwasher. The powerwasher is located on the underside of the headlamp assembly. The powerwasher is located in a clip at the front of the headlamp and secured with 2 self tapping screws to the headlamp body.
The powerwasher is a telescopic unit which extends forwards from the headlamp assembly under washer fluid pressure supplied by the headlamp powerwash pump. When the pump pressure decreases the powerwasher is automatically retracted back into the housing. The outer end of the powerwasher is fitted with a trim which blends the powerwasher into the headlamp when it is not operating. The powerwasher has two washer jets which direct washer fluid under high pressure onto the headlamp lens when the powerwasher is extended.
RAIN/LIGHT SENSOR
The rain/light sensor is located at the upper edge of the windshield, behind the interior rear view mirror. Contact between the rain sensor and windscreen is provided via a silicon pad which is compressed during the assembly process by two locking retaining clips either side of the sensor.
The rain/light sensor unit attaches to the windshield via two clips, which latch onto formed tags on the windshield bracket.
The sensor provides information to the CJB (central junction box) for the optimum wiper operation for the prevailing conditions to maintain the shield in a clear condition at all times. The rain/light sensor is an optical unit, which operates on an infrared waveband. The sensor uses the principle of the laws of reflection on interfacing surfaces between materials with differing refraction properties.
The rain/light sensor is connected to the CJB (central junction box) via a LIN (local interconnect network) bus. The sensor also receives a hardwired power and ground from the CJB (central junction box). The 'auto' wipers are activated when the column stalk is moved to position 1 (first position from off in the upward direction). The sensitivity of the sensor can be adjusted by rotating the sensitivity collar on the wiper column stalk in the clockwise or counterclockwise direction. Clockwise rotation will decrease sensitivity, while counterclockwise adjustment will increase sensitivity. An increase in sensitivity adjustment results in a single wipe of the front wiper motor.
NOTE:
The rain sensor also contains a light sensor. The light sensor is used to control operation of the automatic headlamps function. For additional information, refer to Exterior Lighting Overview
WIPER CONTROL SWITCH
The wiper control switch is located on the RH (right-hand) steering column multifunction switch. The switch allows selection of the following functions:
- Slow wipe
- Fast wipe
- Auto
- Flick wipe
- Windshield wash and headlamp powerwash (if fitted).
All wiper functions are connected to the instrument cluster by a resistor or series of resistors within the switch. The instrument cluster uses the returned current to determine the selected function.
WIPER SERVICE POSITION
The wiper service position allows the wipers to be parked in a position to allow easy access to the wiper blades for replacement. The service position is initiated by pulling the RH (right-hand) steering column multifunction switch towards the steering wheel and pressing the start/stop button to switch on the ignition. The wipers will move and stop in a vertical position on the windshield. The RH (right-hand) steering column multifunction switch can be released and the ignition switched off. The service position is terminated at the next ignition on cycle and the wipers return to their normal park position.