GF91.29-P-0011CA Lumbar Support Adjusting Facility, Function

GF91.29-P-0011CA Lumbar Support Adjusting Facility, Function
- except CODE (409) Left/right front multicontour seat

Function requirements, general
On vehicles with code (275) Memory package (driver seat, steering column, mirror) and without code (242) Electrically adjustable passenger seat with memory
^ Circuit 15R ON or
^ Run-on active
^ No on-board electrical system limp-home mode

Run-on (on vehicles with code (275) Memory package (driver seat, steering column, mirror) and without code (242) Electrically adjustable passenger seat with memory)
The lumbar support adjustment can still be adjusted for 3 minutes after circuit 15R has been switched off.

If, during the run-on time, the circuit status or a door status changes, the run-on time starts again. Even in the event of a change in door status or a change in circuit status after any amount of time, the run-on phase restarts, which means that prior to driving off the lumbar support can also be adjusted after opening a door, without having to switch circuit 15R on.

The rear SAM control unit with fuse and relay module (N10/2) receives the circuit status via the interior CAN (CAN B) by the electronic ignition lock control unit (N73). The rear SAM control unit with fuse and relay module then switches on the power supply for the lumbar support adjustment.

Function requirements on vehicles with code (275) Memory package (driver seat, steering column, mirror) and with code (242) Electrically adjustable passenger seat with memory
^ No on-board electrical system limp-home mode

Lumbar support adjusting facility function description, general
The lumbar support adjusting facility is described on the driver seat for left-hand vehicles by way of an example, but this also applies to the passenger seat.

The backrest in the driver and front passenger seat is equipped with lumbar support (electric 4-way lumbar support) to provide optimum support for the spine. The lumbar support consists of two air cushions each, an electrical driver seat lumbar support pneumatic pump (M25/4) to generate compressed air and the driver seat lumbar support adjustment control unit (N32/23) with integrated control valve block for pneumatic control.

The adjustment is performed via the driver seat lumbar support adjusting facility switch (S109/2), which is connected to the driver seat lumbar support adjustment control unit via a direct electrical line and is located on the exit side of the seat.

The lumbar support adjustment allows the following partial functions:
^ Inflating the air cushions
^ Deflating the air cushions
^ Lumbar support contour height adjustment

Inflating the air cushions
As long as the cross-shaped rocker button of the lumbar support adjusting facility switch is pressed in the "forward arrow" direction, the backrest contour in the lumbar support area is changed by inflating the currently active upper or lower lumbar support air cushions. The differences in pressures in the individual air cushions are retained. On reaching the maximum pressure, the inflation is stopped.

Deflating the air cushions
As long as the cross-shaped rocker button in the lumbar support adjusting facility switch is pressed in the "backward arrow" direction, the lumbar support contour is changed by deflating the air cushions. Deflation begins with the upper air cushion, delayed one second before the lower air cushion.

Lumbar support contour height adjustment
When the cross-shaped rocker button of the lumbar support adjusting facility switch is pressed up or down, the lower or upper air cushion is activated and inflated or deflated separately depending on the request. Here, the ventilation of the one air cushion begins approx. two seconds before the ventilation of the other air cushion that is activated.
- When the cross-shaped rocker button is pressed in the "upward arrow" direction, the air pressure increases in the upper and decreases in the lower air cushion.
- When the cross-shaped rocker button is pressed in the "downward arrow" direction, the air pressure decreases in the upper and increases in the lower air cushion.

The compressed air that is provided is distributed by the lumbar support adjusting facility control unit (with integrated valve block) to the upper and lower air cushions via the pneumatic lines, based on the driver request.

The pressure is also regulated by the lumbar support adjusting facility control unit.