E3020 Windscreen wipers/washers

Description

The windscreen wash/wipe system is operated by a stalk switch on the right side of the steering wheel. The stalk switch can be set to five positions that correspond to different functions:

• windscreen wiper off (standstill);
• intermittent operation;
• continuous slow operation;
• continuous medium-fast operation;
• temporary fast operation (unstable stalk position).

When the stalk switch is set to intermittent operation position, four different speeds can be selected by turning the relevant ring:

• slow intermittent;
• medium intermittent;
• medium-fast intermittent;
• fast intermittent.

The windscreen wiper function is operated by pulling the stalk switch slightly toward the steering wheel. This action operates the washer pump. If the stalk switch is held in position, the windscreen wiper also operates (continuous operation). The windscreen wiper carries on working for a few sweeps after the stalk switch is released.

The entire system is governed by an electronic device which is responsible for controlling the intermittent function and also the windscreen wiper motor and washer pump.

The windscreen wash/wipe circuit is protected by a specific fuse and is operated by the ignition-operated relay located in the junction unit.

The windscreen wiper and washer can be operated with the ignition key turned to ON.

Description of operation

The windscreen wiper control on the steering column switch unit H5 selects the various operating modes of the windscreen wash/wipe.

The stalk unit H5 is supplied at pin 3 of connector D from the ignition-operated line (INT/A) of the relay R1 protected by the fuse F14: both are contained in the junction unit B1.

Depending on the pre-selected function, the stalk unit H5 (connector A) sends the following control signals to the internal electronic device to the windscreen wiper motor N15:

• from pin 2 for continuous fast operation: the signal reaches the motor directly;
• from pins 3, 4 for continuous slow and medium-fast oeration: the signal arrives from the intermittent device and is then sent to the motor
• from pin 5 for intermittent operation: the signal reaches the intermittent device and is then sent to the motor; this signal differs according to adjustment ring position, which adds no resistance, one resistance or two resistances to the line to obain the three different intermittence speeds.

The windscreen wiper motor N15 is then connected to earth. It consists of the actual geared motor, the end of travel contacts and the electronic adjustment and control device.

When operated, the windscreen washer switch on the steering column switch unit H5 sends two signals from pin 8 and pin 9 of connector A, which reach the pump for operating the windscreen washer N20 directly.

One of the two signals (pin 6 of connector A of H5) is also sent to the electronic device inside the windscreen wiper motor N15 which manages the operation of the windscreen wiper coupled with the windscreen washer. The same signal is also sent as a go ahead to allow the operation of the headlamp washers ( Wiring diagram E3022 HEADLAMP WASHERS ).

Wiring diagram

Components

Component location