Seat adjustment driver's side, passenger side

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

• Seat fore/aft adjustment
  
• Seat height adjustment
  
• Seat angle adjustment
  
• Seat depth adjustment
  
• Seat angle adjustment
  
• Backrest width adjustment
  
• Headrest adjustment
  
• Headrest adjustment
  

Brief description of components

Seat module driver's side/passenger side

Depending on equipment, the seats are equipped with different seat modules. In general, there are 2 different module sizes:

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

If the seat is equipped with the special equipment lumbar support adjustment or Active Seat, the module is fitted with a 10-chamber plug connection.

The seat module is secured directly to the corresponding seat.

The seat modules are networked with the vehicle via the CAN BUS.

Centre console switch centre

The control unit centre console switch centre has the following functions:

• CAN BUS interface to the vehicle electrical system
  
• Interface to the seat switches
  
• Interface to the controller
  

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

Operating switch driver seat/passenger seat

Depending on the equipment, various switch blocks are fitted.

The switch blocks are connected by means of ribbon cables to the centre console switch centre (BZM).

Hall sensors, seat position

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

Main functions

Seat adjustment

The seats are adjusted by operating the corresponding switch.

• The adjustment command is transferred from the switch block to the BZM across a ribbon cable.
  
• The BZM sends the message across the K-CAN SYSTEM to the Car Access System (CAS).
  
• The CAS as ”gateway control unit” passes the message on to the corresponding seat module via the K-CAN PERIPHERALS.
  
• 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 monitored to prevent thermal overloading. When a mechanical stop is reached, the activation 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:

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

Headrest

The headrest is a function of the longitudinal seat adjustment.

The headrest is automatically readjusted:

• mechanically with an operating cable in the case of basic seat,
  
• electrically in the case of comfort seat (by identifying the position using Hall sensors). Here, the headrest moves to the corresponding position as soon as the longitudinal adjustment has been completed. In addition, the headrest can be electrically adjusted on an individual basis.
  

Seat memory

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 CAS
  
• Memory key of BZM
  

The information is simultaneously sent to the following control units:

• the front door modules for the mirror memory position
  
• the CIM (Chassis Integration Module) for the steering column memory position
  

Operation of the seat memory

Programming

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 of seat, steering column and rear view mirror.
  

Retrieval

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

• Touch button operation: Touching the desired position button causes the drives to move into the corresponding position. The one-touch function is only possible with terminal 15 off.
  
• Continuous button operation: The drives only run as long as the desired position button is pressed. If the button is released before the target position is reached, the drives are switched off immediately. The positioning procedure is continued when the position button is pressed again.