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

MODEL 218 with CODE 275 (Electrically adjustable front seats memory package) without CODE 409 (Left/right front multicontour seat) without CODE 432 (Active multicontour seat) 

Shown on left seat 

Location 

The lumbar support adjustment control unit is located off-center in the respective seat backrest frame behind the backrest trim.

Tasks 

The lumbar support adjustment control unit has the following tasks:

• Regulation of the air cushion pressures in the two lumbar support cushions of each front seat
• Storage of last adjusted lumbar support contour
• Control of driver seat lumbar support pneumatic pump (M25/4) or front passenger seat lumbar support pneumatic pump (M25/5)
• Reading in of signals from the driver seat lumbar support setting switch (S109/2) and the front passenger seat lumbar support setting switch (S109/3)

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 a direct line:

• Driver seat lumbar support adjustment switch
• Front passenger seat lumbar support adjustment switch

A pressure sensor is integrated in the respective lumbar support adjustment control unit.

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 following component is actuated via a direct line:

• Driver seat lumbar support pneumatic pump or front passenger seat lumbar support pneumatic pump, for controlling the compressed air supply

The air cushions in the seat are actuated via valves integrated in the lumbar support adjustment control unit.

Body 

The following parts are integrated into the housing of the lumbar support setting control unit:

• Microprocessor
• Pressure sensor
• Valves

Lumbar support wiring diagram

PE91.29-P-2109-97XAA