Active Seat, Driver's Side, Passenger Side

Active Seat
The active seat serves to relax the back muscles and spinal column.

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.

Center console switch center
The control module center console switch center has the following functions:
- CAN BUS interface to the vehicle electrical system
- Interface to the seat switches
- Interface to the controller
The control module center console switch center is fitted in the front center 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 center console switch center (BZM).

Active Seat
Each seat contains:
- 2 fluid bubbles
- 1 hydraulic pump
- 1 solenoid valve
- 2 under-pressure switches

Fluid bubbles
The fluid bubbles are filled with a water-glysantine mixture. They are connected to the pump unit by means of plastic hoses.

Hydraulic pump
Pump with alternating direction of rotation for filling and emptying the fluid bubbles

Solenoid valve
The solenoid valve opens and closes the inlet to the fluid bubbles.

Under-pressure switches
Each fluid bubble contains an under-pressure switch.
Both switches are arranged in line in the circuit as openers.

Main functions
Activation of active seat
The active seat is activated by pressing 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 module" passes the message on to the corresponding seat module via the K-CAN PERIPHERALS.
- The seat module activates the hydraulic pump and the solenoid valve directly via its output stages.

Function sequence, active seat
The system is filled with a defined quantity of fluid.
- The hydraulic pump pumps the fluid alternately into the left and right fluid bubble. In the end positions and middle position, the procedure is interrupted briefly.
- The solenoid valve opens and closes the inlet to the fluid bubbles. The solenoid valve is closed when the system is switched off and in the pauses between the adjustments.
- The under-pressure switches detect the end positions. In addition, the seat module senses the middle position (by dividing the time between the switch operations in two).
- The middle position is learned by the seat module.
At high vehicle lateral acceleration, the procedure of the active seat is interrupted. The lateral acceleration signal is provided by the yaw rate sensor via the bus system.

Safety function
Consumer shutdown
In the case of signal �Control peak reduction priority� from the power module, the power of the seat heating is reduced or it is switched off.

The function indicator (LEDs) remains switched on when the active seat is switched off for a brief period.