Stalk unit

Description 5550A

INTRODUCTION

The diagram illustrates the controls for the steering column switch unit.

SPECIFICATIONS:

The diagram illustrates the steering column switch unit controls.

A - Steering column switch unit

B - Lights/direction indicators/trip computer controls

C - Side ilghts control

D - Rearscreen wiper control

E - Windscreen wiper controls

F - Pump controls

G - Electric pump

H - Electronic module

I - Windscreen wiper motor

L - Rearscreen wiper motor

LIGHTS/DIRECTION INDICATORS CONTROLS OUTPUT INTERFACES (BETWEEN STEERING COLUMN SWITCH UNIT AND BODY COMPUTER)

BC1: Left direction control

BC2: Right direction control

BC3: Dipped headlamps control

BC4: Main beam headlamps control

BC6: Side lights control

TR: Trip computer control

WASH/WIPE INPUT CONTROLS INTERFACES

TC3: Windscreen wiper zeroing cam: this cam is a switch fitted on the motor which is normally closed when the wiper is in the rest position (windscreen wiper blades downwards and still).

TL2: Rearscreen wiper zeroing cam: this cam is a switched fitted to the motor which is normally open when the wiper is in the rest positino (rearscreen wiper blade downwards and still). All the above signals are the active earthed type.

RM: Reverse gear engaged signal: the control provides an active signal at +15 when reverse gear is engaged. The same control supplies the reversing lights.

TCI-TC2: windscreen wiper control outputs;

TL1: rearscreen wiper control output;

P1-P2: electric pump control outputs;

BC5: headlamp washer go ahead to Body Computer. The electronic module supplies a positive comman.

RAIN SENSOR INTERFACES

The rain sensor should be supplied when the right lever is in the AUTOMATIC position:

• RS2: Rain sensor supply circuit by output electronic module (wiper functions);
• RS1: Hardware interface between rain sensor and input electronic module.

COMPONENTS AND OPERATION

THE CASING

It is a part of the steering column switch unit containing the electrical circuits and the switching and automatic release mechanisms which return the left lever to the rest position once the steering wheel has been realigned. Attachment angle 80° ± 5° release angle 60° ± 5°.

1 - Right lever with front/rear wiper controls

2 - Left lever with lighting/direction indicator controls

3 - Horn/radio controls cable

4 - Air Bag clock spring

5 - Trip computer control button

6 - Internal electronic module

ABC - Connectors

The front part of the CASING houses the CLOCK SPRING which provides the interface with the steering wheel.

At the rear is the collar with a retaining band for fastening it to the steering column and additional attachments which guarantee the axial and angular position of the steering column switch unit on the steering column.

The steering column switch unit casing contains the fastenings for the upper and lower half casings.

The ELECTRONIC MODULE is connected to the CASING.

The rear of the CASING contains the housings for the electrical connectors.

ELECTRONIC MODULE

This is the electronic control unit which controls the wiping functions and is mechanically secured to the CASING to which it is electrically connected by means of special terminals.

It controls the operation of:

• Windscreen wiper: Sstroke frequency for all trim levels;
• Rearscreen wiper: stroke frequency and power assistance in reverse gear;
• Windscreen washer function: 'Smart' washing for all versions;
• Rearscreen washer function:'Smart' washing for all versions;
• Rain sensor: Management of signal coming from sensor - de-luxe version

CLOCK SPRING

It has two functions:

• to transmit the rotation of the steering wheel to the automatic release mechanism inside the CASING.
• to transfer the electrical signal for the controls on the steering column (horn and other optional serves) and connect the AIR-BAG module.

MULTI-PURPOSE SWITCH OR LEFT LEVER

It includes the lighting and direction indicator controls.

All the commands are activated via the lever or the ring nut at the end of the actual lever.

A - Main lights switch; (on ring nut)

B - Dipped / main beam headlamps switch; (on lever)

C - Control for flasher - main beam (on lever)

D - Control for direction indicators and lane change; (on lever)

Main lights switch

This control is at the end of the lever and is activated by turning a special ring nut.

There are 3 stable positions for the ring nut when it is rotated in an anti-clockwise direction:

• Pos. 1 = No circuit switched on
• Pos. 2 = Side lights
• Pos. 3 = Side lights + go ahead for dipped/main beam headlamps + rear fog lamp.

All the ring nut manoeuvres (from 1 to 3 and viceversa) should only be possible with the left lever in the dipped headlamps position, it should not be possible to make the above movements with the lever in the main beam headlamps position.

Dipped/main beam headlamps switch

The operation is achieved by moving the lever perpendicular to the steering column (in other words lever moved from the rest position towards the dashboard).

The control has two STABLE type positions, intermediat positions are not permissible.

It is only possible to switch the dipped / main beam headlamps with the main lights switch (A) in position 3.

Control for flasher - main beam

This operated by pulling the lever from the rest position towards the centre of the steering wheel, the action is UNSTABLE as a result of which when the lever is released it returns to the rest position.

Direction indicators control

The direction indicators are operated by moving the lever on the steering wheel plane in two directions - clockwise and anti-clockwise.

The automatic release device intervenes for each STABLE position of the direction indicators and has the function of returning the lever to the rest position after the steering wheel has been realigned.

Fog lights control

The fog lights are activated by pressing a special button in the centre switch panel, thereby sending a signal to the body computer which, in turn, verifies and validates the activation.

The body computer implements the following strategies: with the side lights/dipped headlamps on, the fog lights can be activated. When the main beam headlamps comes on as well, still with the fog lights on, the dipped headlamps are switched off automatically (to prevent the excessive build up of heat in the light cluster). When the main beam headlamps are flashed, the fog lights remain on.

MULTI-PURPOSE SWITCH OR RIGHT LEVER

This includes the front and rear wiper controls. All the commands are activated via the lever or the ring nuts on the actual lever. There is also a button on the end of the lever which controls the trip computer functions.

A - Windscreen wiper operation;

A1 - Windscreen wiper intermittent adjustment / Rain sensor sensitivity;

B - Windscreen washer operation;

C - Rearscreen wiper operation;

D - Rearscreen washer operation;

E - Trip computer control button

Windscreen wiper operation (lever a)

The operation is achieved by moving the lever on the steering wheel, there are 5 different positions:

Pos. 1 = No circuit switched on (STABLE): REST POSITION;

Pos. 2 = Antipanic function (UNSTABLE): ANTI-CLOCKWISE DIRECTION;

Pos. 3 = Intermittent / Automatic (STABLE): CLOCKWISE DIRECTION;

Pos. 4 = 1ST SPEED continuous (STABLE): CLOCKWISE DIRECTION;

Pos. 5 = 2ND SPEED continuous (STABLE): CLOCKWISE DIRECTION;

Windscreen wiper intermittent adjustment / rain sensor sensitivity (ring nut a1)

This control is at the end of the lever and is operated by rotating a special ring nut in a clockwise direction in 4 stable positions corresponding to:

• BASIC TRIM LEVEL: from Pos. 1 to Pos. 4 = Increasing wiping frequency;
• DE-LUXE TRIM LEVEL: from Pos. 1 to Pos. 4 = Increasing rain sensor sensitivity;

ELECTRONIC MODULE (INCORPORATED IN STEERING COLUMN SWITCH UNIT)

This is the electronic control unit which controls the operation of the electric windscreen and rearscreen wiper motors and the smart washing functions; it is fixed mechanically to the CASING to which it is electrically connected by means of special terminals.

In particular, it controls the operation of the:

• Windscreen wiper (stroke frequency for all trim levels);
• Rearscreen wiper (stroke frequency and power assistance in reverse gear);
• Windscreen washer function ('smart' washing for all versions);
• Rearscreen washer function ('smart' washing for all versions);
• Rain sensor (management of signal coming from sensor - de-luxe version)

Compositino and operation in detail of windscreen wiper functions: also see subassembly 5050 windscreen washer and headlamp washer.

REARSCREEN WASH/WIPE

This device has the task of cleaning the rearscreen effectively.

It consists of a single motor with a 12 V supply which can operate at voltages between 9 and 16 V; it has a twin metallic type overload cut-out and does not have protection against radio interference.

The wiper is constructed from a single wiper element made of a plastic arm and the linkage is internal. The jet is incorporated in the engine dust cover.

C - Rearscreen wiper control

D - Rearscreen washer control

Rearscreen wiper control (ring nut c)

This control is on the lever and is activated by turning a special ring nut.

The control has 2 STABLE positions and is turned in a clockwise direction:

• Pos. 1 = No circuit switched on;
• Pos. 2 = Rearscreen wiper operating intermittently;

All the instructions given for the operation of the windscreen wiper are valid.

Rearscreen washer operation (lever d)

It is operated by pushing the lever towards the dashboard, the operation is UNSTABLE as a result of which when the lever is released it returns to the rest position.

The activation of the control involves the simultaneous operation of the rearscreen wiper with the 'smart washing' function (windscreen washer function).

Composition and operation of rearscreen wiper functions in detail: also see subassembly 5050 windscreen washer and headlamp washer.

STEERING COLUMN SWITCH UNIT ELECTRONIC MODULE PIN-OUT

Rear view

1 - Right lever for front/rear wiper controls

2 - Left lever for lighting/direction indicator controls

A - Right lever connector

B-C - Steering column switch unit connectors rear view

Connector A Pin Out

Connector B Pin Out

Connector C Pin Out

SWITCH UNIT WITH CRUISE CONTROL VARIANT

The engine managment systems for petrol engines with motorized throttles and diesel engines with electronically controlled injection times include the Cruise Control function, i.e. a system which automatically maintains the cruising speed set by the driver.

1 - Cruise Control lever

2 - Lights/direction indicator control lever

3 - Front/rear window wipers lever

4 - Air Bag clock spring

5 - Horn/radio controls cable

The Cruise Control lever is integrated in the steering column switch unit, the third lever incorporates the following controls:

• a switch with a ring nut for activating/deactivating the Cruise Control;
• a switch with a ring nut with the function of memorizing the vehicle speed increase/decrease;
• a Resume button for recalling the memorised speed.

Composition and operation of Cruise Control functions: see also subassembly 5580 'SPECIAL ACCESSORIES.