Wiper and Washer Systems: Description and Operation

Wash/Wipe System

Wash/wipe system
The wipe/wash functions can be used after terminal 30B ON.
The windscreen wipers are driven by an electric motor with a reduction gear.
The windscreen wipers are activated by the wiper module. The wiper module is connected via the local interconnect network bus to the junction box electronics (JBE).
The rear wiper is activated directly by the junction box electronics (JBE).The same applies to the washer jet heating.
The rain/driving light sensor is fitted as standard.This generally enables an automatic mode for the windscreen wipers.
A headlight cleaning system is offered as special equipment. The headlight cleaning system is mandatory on vehicles equipped with "Bi-xenon for low-beam/high beam headlights" in countries with approval for Europe. The Touring has a rear window wiper as series standard with a separate rear window washer pump.

Brief component description
The following components supply an input signal for the wipe / wash function:

Wash/wipe switch
The wash/wipe switch is operated by briefly moving the lever. The wiper switch does not lock into place. The signal from the wash/wipe switch is forwarded by the steering column switch cluster (SZL) to the central gateway module (ZGM). From the ZGM control unit, the signal is then sent to the junction box electronics (JBE).
The axial button on the wiper switch activates the automatic mode (automatic control via the rain/driving light sensor). If the automatic mode is disabled, intermittent operation is controlled on a speed-dependent basis.

Rain/driving light sensor
The rain/driving light sensor is located on the windscreen in the mirror base. The rain/driving light sensor consists of a driving light sensor and a rain sensor. It picks up the rain intensity for wiper control and surrounding brightness for control of the low-beam headlights.
The rain/driving light sensor is connected to the junction box electronics (JBE) via a local interconnect network bus.

Wiper module
The windscreen wipers are operated by the wiper module.
The wiper module is activated by the junction box electronics.
The wiper module is connected via a local interconnect network bus to the junction box electronics (JBE).

The following control units are involved in wash/wipe system functions:

JBE: Junction Box Electronics
The junction box electronics (JBE) activates the wash/wipe system (also the wash/wipe system for the rear window on the Touring).
The junction box electronics (JBE) are connected through the body controller area network to the:
- Central gateway module (ZGM)
The junction box electronics (JBE) are connected through the local interconnect network bus to the:
- Wiper module
- Rain/driving light sensor

SZL: Steering column switch cluster
The steering column switch cluster (SZL) forms the interface between the wash/wipe switch and the central gateway module (ZGM).

ZGM: Central gateway module
The central gateway module (ZGM) forms the gateway between the body controller area network and the wash/wipe switch.

The following actuators are activated for the wipe / wash function:

Wiper drive
The wiper system is a two‐arm synchronized system with stroke control (jointed in four places).
The wiper drive is a rotary motor without an electronic module.The wiper motor is located in the wiper module. The wiper module is activated by the junction box electronics (JBE) through a double relay.The end position (rest position) of the wiper motor is detected by a reset contact integrated in the wiper motor.Touring:
The rear wiper motor is mounted on the rear window.
The rear wiper motor is activated by the junction box electronics (JBE) through a relay.
The end position (rest position) of the rear wiper motor is detected by a reset contact integrated in the wiper motor.

Washer pump for windscreen and rear window (Touring)
Both wash pumps are attached to the washer fluid container. The windscreen washer pumps are activated by the junction box electronics (JBE). The washer jets cannot be adjusted. The washer jets generate a pulsating fan shaped spray jet.

Washer pump for headlight cleaning system
The headlight cleaning system is optional equipment.
The washer pump for the headlight-cleaning system is attached to the washer fluid container.
The headlight cleaning system is activated through a relay by the junction box electronics (JBE).

Washer jet heating
The washer-jet heater system prevents the washer jets freezing in cold weather.
The washer jet heating is activated by the junction box electronics depending on the ambient temperature (less than 3 °C).
The washer jet heating system consists of heating resistors.

System functions
The wash / wipe system includes the following functions:
- Wipe functions
- Intermittent wipe
- Wiper stage 1
- Wiper stage 2
- Automatic wiping via rain/driving light sensor

Touring: The rear window is wiped intermittently (intermittent period is programmable by the customer, see Owners Handbook).
With the rear window opened (via rear window contact switch), no wiper operation is permitted.
With reverse gear engaged, a switch is made from intermittent operation to continuous wiping.

Wash function for windscreen and rear window (Touring)
The wash function is available after terminal 30B ON.
To operate the windscreen washer, the wiper switch is pulled backwards (towards driver).
Touring: To wash the rear window, the wiper switch must be pushed forwards (away from the driver) (speed 2).
The washer pump is activated for the activation time. If the wiper switch is activated for a very short time (less than 300 ms), only the washer pump is activated. If it is actuated for a longer period, the wiper is added with a delay. After the washer pump is switched off, the windscreen is wiped for 3 wipe cycles to wipe the windscreen dry.

Headlight cleaning system
When the low-beam headlights are switched on, the headlights are washed every 10th time the windscreen washer is operated.
After ignition ON and low-beam headlights ON:
The headlights are also cleaned with the 1st wash for the windscreen.

Sequence of the wash cycle:
- 0.7 seconds ON
- 1.3 seconds OFF
- 0.7 seconds ON
After headlight cleaning, no other wash cycle can be triggered for 10 minutes (anti-repeat circuit). The repeat interlock is reset by terminal 30B OFF.

Safety function
The signal of the reset contact on the wiper motor (also rear window wiper on the Touring) is used as locking protection for the wiper motor. If the signal is not sent by the reset contact when the wiper motor is switched on, the wiper motor is switched off.
Switching on the wiper motor again is only possible once.Thereafter, the wiper motor can only be switched on under the following conditions:
- 3 minutes have elapsed
- Terminal 30B OFF, terminal 30B ON
The wiper drive can only be switched on using the wash/wipe switch (not automatic due to danger of injury). With blocking protection detected, the wash pumps for the windscreen and the headlights can be activated another 3 times.

Notes for Service department

General notes

Washer jets
The washer jets cannot be adjusted. The washer jets cover the entire window glass (fan-shaped jet). The customer or the workshop cannot adjust the spray pattern.

Notes on encoding/programming

IMPORTANT: The junction box electronics must be encoded after renewing the wiper module (JBE).

No liability can be accepted for printing or other faults. Subject to changes of a technical nature