Component Description For Lumbar Support Control Unit - GF91.29-P-5281GR

MODEL 166 up to model year 2016 with CODE 275 (Memory package (driver seat, steering column, mirrors))

MODEL 166 up to model year 2016 with CODE 560 (Left and right electrically adjustable driver seat)

MODEL 166 up to model year 2016 with CODE P64 (Memory package)

Shown on driver seat

Fig 1: Lumbar Support Control Unit Component Location - Model 166 Up To MY 2016 With Code 275, 560, P64

Courtesy of MERCEDES-BENZ USA

Location

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

Task

The lumbar support adjustment control unit has the following tasks:

Regulation of the air cushion pressures in the two lumbar support cushions of each 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 the voltage-coded driver seat lumbar support adjustment switch (S109/2) or front passenger seat lumbar support adjustment switch (S109/3)

The tasks are subdivided as follows:

Reading in of switches, 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 or front passenger seat lumbar support adjustment switch
Internal pressure sensor

Evaluation of input factors

The signals that have been read in are evaluated by the lumbar support adjustment control unit and the corresponding components are then actuated.

Actuation of components

The driver seat lumbar support pneumatic pump or front passenger seat lumbar support pneumatic pump is actuated via a direct line.

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

Body

A pressure sensor is also integrated in the lumbar support adjustment control unit housing along with a microprocessor. This sensor is used for detecting and monitoring the pressure. The air pressures in the cushions are adjusted by the valves integrated in the lumbar support adjustment control unit.

Lumbar support wiring diagram

PE91.29-P-2109-97NAA