Lumbar Support Control Unit, Component Description - GF91.29-P-5281FR
Model 257, 290 up to Model year 2021 with code 275 (Memory Package (driver's seat, steering column and mirror)) except code 432 (Dynamic seats left and right)
Model 257, 290 up to Model year 2021 with code 278 (Fully electric front seats)
Model 290 up to Model year 2021 with code P65 (Ergonomics package)
Shown on driver seat
Location
The lumbar support adjustment control units are centrally installed in the respective backrest frame behind the backrest trim.
Task
The lumbar support adjustment control units have the following tasks:
- Control of air cushion pressure in the lumbar support of the respective seat
- Storage of last lumbar support contour setting
- Control of the driver seat lumbar support pneumatic pump (M25/4) or front passenger seat lumbar support pneumatic pump (M25/5)
The tasks are subdivided as follows:
- Reading in of sensors and signals
- Evaluation of input factors
- Actuation of components
Reading in of sensors and signals
The signals from the following components are read via direct lines:
- Driver seat lumbar support adjustment switch (S109/2)
- Front passenger seat lumbar support adjustment switch (S109/3)
- Internal pressure sensor
Evaluation of input factors
The read-in input factors are evaluated by the respective lumbar support adjustment control unit. The relevant components are then actuated.
Actuation of components
The actuation of the driver seat lumbar support pneumatic pump or front passenger seat lumbar support pneumatic pump for controlling the compressed air supply occurs via a direct line.
The air cushions in the seat are actuated via valves integrated in the respective lumbar support adjustment control unit.
| Wiring diagram for lumbar support control unit | PE91.29-P-2113-97XBA |