Seat adjustment driver's side, passenger side

Depending on equipment, the following adjustments to the front seats are possible:

• Seat fore/aft adjustment
  
• Seat height adjustment
  
• Seat angle adjustment
  
• Seat angle adjustment
  
• Headrest adjustment
  

Brief description of components

Seat module driver's side/passenger's side

Depending on equipment, the front seats are equipped with different seat modules. Two module sizes are used:

• Module with 10-chamber plug connection
  
• Module with 8-chamber plug connection
  

In the case of seats with an adjustable lumbar support, the module with 10-chamber plug connection is used.

The seat module is fitted in the corresponding seat.

The seat modules are linked across the K CAN PERIPHERALS data bus to the control units of the body area.

Control panel module, centre console (BZM)

The centre console switch centre control unit is

• the interface from the K CAN SYSTEM data bus to the control units of the body area,
  
• the interface to the seat switches and
  
• the interface to the controller (CON).
  

The control unit centre console switch centre is fitted in the front centre armrest.

Operating switch driver seat/passenger seat

The switch blocks for driver's seat/passenger seat are connected by means of ribbon cables with the centre console switch centre (BZM).

Hall sensors, seat position

With the seat memory equipment, servomotors with Hall sensors are fitted for position activation.

Main functions

Seat adjustment

The seat adjustment is triggered by pressing the corresponding switch.

• The adjustment request is transferred from the switch block across a ribbon cable to the centre console switch centre (BZM).
  
• The centre console switch centre (BZM) makes the message available to the Car Access System (CAS) across the K CAN SYSTEM data bus.
  
• The Car Access System (CAS) is the ”gateway control unit” and it forwards the message across the K CAN PERIPHERALS data bus to the corresponding seat module.
  
• The seat module activates the adjustment motor directly via its final stages. Simultaneously, a maximum of 3 motors are activated.
  

The total running time of each adjusting motor is determined and stored to prevent thermal overloading. When a mechanical stop is reached, activation of an adjusting motor is stopped. The mechanical stop is detected via the increased current intake.

In the case of the Memory seat, the position of the mechanical stops is saved after the first identification. For subsequent adjustments, the seat stops before this position is reached (soft stop).

In the case of comfort seat, 4 adjustment directions are equipped with soft start: These are:

• Seat fore/aft adjustment
  
• Seat height adjustment
  
• Seat angle adjustment
  
• Seat angle adjustment
  

Headrest adjustment

In addition, the headrest can be electrically adjusted on an individual basis.

Seat memory positions

The seat memory control unit provides the possibility to store various seat positions.

To run the stored seat position, the seat memory control unit requires information:

• Key number from the Car access System (CAS) and
  
• Memory key operation from the centre console switch centre (BZM).
  

The information is simultaneously sent to the following control units:

• Door modules in the driver and passenger door for the mirror memory position
  
• CIM (Chassis Integration Module) for the steering column memory position.
  

Operation of the seat memory

Programming/storage

Seat positions can only be programmed as of terminal R.

Saving a seat position:

• Press the memory key ”M”: The programming readiness is active for 7 seconds.
  Programming readiness is indicated by the Memory button lighting up.
  
• Press position button: adoption of current position data of seat, steering column and rear view mirror.
  

Retrieval

A distinction is made between two operating modes when stored driver's seat positions are retrieved:

• Touch button operation: Touching the corresponding position button causes the drives to move into the desired position. The one-touch function is only possible with terminal 15 off.
  
• Continuous button operation: The drive runs as long as the corresponding position button is pressed. If the position button is released before the target position is reached, the drive is switched off. If the button is pressed again, procedure for the new position is resumed.