Component description for lumbar support control unit - GF91.29-P-5281CA

MODEL 207.3/4 without CODE 409 (Left/right front multicontour seat) 

Shown on front passenger seat on model 207.4 with code (403) 

Fig 1: Identifying Lumbar Support Control Unit Components - Shown On Model 207.4

Courtesy of MERCEDES-BENZ USA

Location 

The lumbar support adjustment control unit is installed displaced off-center in the corresponding seat backrest frame behind the backrest trim.

Tasks 

The lumbar support adjustment control units have the following tasks:

• Reading in of the voltage-coded signals of the driver seat lumbar support adjustment switch (S109/2) or front passenger seat lumbar support adjustment switch (S109/3)
• Actuation of the driver seat lumbar support pneumatic pump (M25/4) or front passenger seat lumbar support pneumatic pump (M25/5)
• Control of the air cushion pressures in both lumbar support cushions
• Storage of last adjusted lumbar support contour

The tasks are subdivided as follows:

• Reading in of signals 
• Evaluation of input factors 
• Actuation of components 

Reading in of signals 

The signals from the following components are read via direct lines:

• Driver seat lumbar support adjustment switch
• Front passenger seat lumbar support adjustment switch
• Integrated pressure sensor

Evaluation of input factors 

The read-in input factors are evaluated by the lumbar support adjustment control unit. The air cushions in the seat are actuated via valves integrated in the lumbar support adjustment control unit.

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 lumbar support adjustment control unit.

Body 

The air pressures in the cushions are adjusted by the valves integrated in the lumbar support adjustment control unit.