Vauxhall Workshop Service and Repair Manuals

Wiper/Washer System Description and Operation

Wiper/Washer System Components

The wiper/washer system consists of the following electrical components:

Windshield Wiper System

On Wiper System Smart equipped vehicles, the body control module (BCM) will command front wiper operations via local interconnect network (LIN) serial data communications instead of via ON/OFF and HIGH/LOW Wiper Motor Relay Drive Outputs. In front wiper systems using the Wiper System Smart - Single configuration, the Driver's side and Passenger's side Wiper Arm are connected by a mechanical linkage with a single integrated Front Wiper Motor/Controller operating them. The Front Wiper Motor/Controller contains the necessary electronics, motor, and position sensors to execute front wiper commands from the Body Control Module. These internal electronics are integrated into the cover of the wiper motor gear housing and are not considered a serviceable item. The Front Wiper Motor/Controller wipes the front windshield by controlling the up and down wiper arm movement by the use of a reversing motor and an internal position sensor. The sensor keeps track of the gear wheel position and when the Controller determines that the wiper arms are at a position to reverse direction, it reverses the motor supply voltage by use of its internal motor control circuitry. The interface between the BCM and the Front Wiper Motor/Controller utilizes a Master/Slave configuration using a LIN serial data system for communication. The BCM is designated as the master, and the Front Wiper Motor/Controller is configured as the slave. As the System Master, the BCM uses the LIN communication bus to command Front Wiper operation, and communicate vehicle information to the Wiper Motor controller. The Front Wiper Motor/Controller provides system status and diagnostic information to the BCM for diagnostic reporting and operational purposes. The Body Control Module (BCM) also provides a hardwired redundant output that switches Battery power to the Wiper Motor upon activation of its low assertion High Speed Wiper Switch input. The BCM will do this, even if the module has lost all microprocessor control. The Front Wiper Motor/Controller gives priority to its LIN input over this Redundant Control Input, however, in the event that LIN communications are lost between the BCM and the Front Wiper Motor/Controller this redundant signal is used to command the required fail-soft wiper actions including Power Mode. While under Redundant Input control the Front Wiper Motor/Controller shall provide Continuous Low Speed Wiper operation when the input is Active, and will park the Wipers and go to Low Power Mode when the Redundant Input is Inactive.

While the Front Wiper Switch is either held in the MIST position (momentary contact switch) or is in its LOW position (latching switch), the BCM provides continuous Low Speed Wiper operation by commanding uninterrupted Low Speed Wiper operation by setting the transmitted LIN signal to Low Speed Wipe.

The BCM shall command the Wiper System Smart to perform Intermittent Wipes as follows:

As called out above, the wipe delay interval is a function of the INTERMITTENT Delay Interval Switch setting. When enabled, the Intermittent with Speed feature affects each of the 5 normal Intermittent Delay Intervals as a function of vehicle Speed. The Delay Intervals shall be biased to a shorter delay period with faster vehicle speeds and to a longer delay period with a slower vehicle speed.

Windshield Washer System

The BCM controls the windshield wash operation and windshield wash activated wiper operation. When the BCM detects the activation of the momentary windshield wash control switch, it activates its washer pump relay drive output which supplies battery power to the coil of the washer pump relay. This energizes the relay, which switches battery power to the pump motor. The BCM will also activate continuous low speed windshield wipes as described above. Upon deactivation of the windshield wash control switch, the wiper control module (BCM) shall deactivate the wash motor and will also park the wiper motor as described above unless the drip wipe feature is enabled. On some vehicles the drip wipe feature will be enabled and cause the system to provide additional wiping of the windshield after the switch has been released and fluid is no longer being applied. The front wash feature may attempt to detect a stuck switch. When enabled, activation of the wash feature shall be limited to 10 s.

On vehicles with the Rear Wash feature a single reversing wash motor may be utilized for both the front and rear wash operation. In this system the wash motor is operated in one direction to spray fluid on the front windshield and then operated in the reverse direction to spray fluid on the rear window. The BCM Controls the reversing wash motor through two High Side Drive outputs. One controls the Front Wiper Motor Relay and one controls the Rear Wiper Relay.

Headlamp Washer System

When Headlamp Wash Equipped, the headlamps shall be sprayed with wash fluid as a result of an extended Windshield Wash Switch Activation. In order to preserve wash fluid, the feature shall only be allowed to activate if the Low or High Beam Headlamps are active. In addition, after the initial Headlamp Wash operation has been performed, additional headlamp washes shall not be performed for the next 4 Windshield Wash activations or for 48 h whichever comes first. In the event that the system has detected a Stuck Front Wash Switch condition, the Headlamp Wash Feature shall be disabled.

Rain Sense Mode and Rain Sense Indicator

When this feature is activated on rain sense equipped vehicles, the wiper subsystem performs front windshield wipes according to the amount of moisture detected on the windshield. The BCM will control the wiper motor speed, as indicated above, based on wipe requests that it receives from a moisture sensor (rain sense module) which is mechanically attached to the windshield through a windshield mounted optic coupler. The system uses a master/slave configuration utilizing a local interconnect network (LIN) based serial data communication system. The BCM is designated as the master, while the rain sense module is designated the slave. As the system master, the BCM uses the LIN serial communication bus to enable or disable rain sense module operation, communicate wiper control switch settings, and wiper motor position information to the rain sense module. The rain sense module requests wiper motor function, and provides the BCM with system status and diagnostic information for diagnostic reporting. When this feature is present, the BCM uses the front wiper control switch's intermittent 1 thru intermittent 5 settings to activate the system and to act as the automatic wiper sensitivity control. This allows the driver to adjust the moisture level at which the rain Sensor requests the BCM to automatically wipe the windshield. The intermittent 1 setting corresponds to the lowest sensitivity and intermittent 5 the highest sensitivity.

Some vehicles (if calibrated) shall display an AUTO front wiper indicator when the feature is active. This indicator shall notify the driver of the vehicle that the rain sensor is ready to perform automatic wiping of the windshield upon detection of moisture.

This indicator shall be requested when all of the following are true:

The above indicator shall be turned OFF when any of the following become true:

Rear Wiper System

On vehicles equipped with a rear wiper, the BCM determines of the Rear Wipe/Wash System Mode of Operation by monitoring the multiplexed output of the Rear Wipe/Wash Switch. The Rear Wipe Wash Switch uses a reference ground signal from the BCM. The BCM provides a switched battery pull-up for the Rear Wiper/Washer Switch output signal it receives. All the BCM inputs are recognized as active when the Rear Wiper Switch provides a path to the referenced ground signal. The Rear Wiper/Washer signal received by the BCM is the result of 3 resistors in the Rear Wiper Switch configured as a resistor ladder network. This signal is connected to a BCM Analog to Digital Input which also provides a switched battery pull-up for the circuit. Depending on the function selected (Low, Intermittent, Off, Wash), the Rear Wiper Control Switch connects a different set of resistors into the circuit resulting in different voltages appearing on the BCM A/D input. By monitoring this voltage, the BCM determines how to control the Rear Wiper Motor Relay and the Rear Washer Relay.

The BCM controls the single speed Rear Wiper Motor by its Active High output to the external Rear Wiper Motor Relay. When the BCM activates its output and applies battery to the coil of the relay, the relay energizes, allowing battery voltage from the fuse to be applied through the switched contacts of the Rear Wiper Motor Relay to the Rear Wiper Motor control input. The motor then operates continuously at low speed. The BCM does not control the parking of the Rear Wiper Motor, it is self parking. When the BCM deactivates its output, the contacts of the Rear Wiper Motor Relay switch back to ground which will be used by the wiper for Dynamic Braking. The rear wiper internal park switch and circuitry will sustain motor operation until the wiper arm has returned to its Park position.

Rear Wash

When the body control module detects that the rear wiper/wash switch has activated the momentary Wash switch, it activates a High Side Drive output which supplies battery to the coil of the Rear Washer Pump Relay. This energizes the relay, which switches Battery Power to the Washer Pump Motor. The BCM will also activate continuous Low Speed Windshield Wipers as described above. The BCM software will attempt to detect a stuck Rear Wash Switch. A stuck Rear Wash Switch condition is detected if the Rear Wash Motor Relay Output has been continuously active for 10 seconds or more. Upon detecting this the BCM will fail soft the state of the Rear Wash Control to Inactive. This shall cause the system to perform as if the momentary wash control had been released.