Lumbar support, driver's side, passenger side

The pneumatic lumbar support can be used to adjust the contour of the backrest on an individual basis.

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).

Lumbar support

Each seat contains:

• 2 inflatable cushions
  
• 4 solenoid valves
  
• 1 air pump
  

Main functions

Lumbar support adjustment

The lumbar support adjustment is achieved by means of 2 inflatable cushions in the backrest. The air chambers are each inflated or deflated by means of 2 solenoid valves. The necessary air pressure is provided by the air pump.

The air pump and solenoid valves are activated by the relevant seat module in such a way that the required contour is set up with the desired hardness.

The desired lumbar support setting can be chosen via the operating 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 corresponding solenoid valve and, if applicable, the air pump.