Lumbar adjustment function - GF91.29-P-0008CA

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

Fig 1: Lumbar Adjustment Block Diagram

Courtesy of MERCEDES-BENZ USA

Function requirements, general 

• Circuit 15R ON or run-on active
• No overvoltage or undervoltage
• No on-board electrical system limp-home mode

If circuit 15R is switched off, the lumbar support can still be set for t = 180 s (run-on time). If, during the run-on time, the circuits status or the door status is changed, the run-on time starts again.

Lumbar support adjustment, general 

To achieve optimum support of the vertebral column, the backrests on the driver and front passenger seat are each equipped with a lumbar support unit.

The lumbar support unit consists of the following components:

• two air cushions
• Lumbar support pneumatic pump
• Lumbar support adjustment control unit

Function sequence for lumbar support adjustment 

Setting is performed via the lumbar support adjustment switch. Pressing of the lumbar support adjustment switch is read in directly by the lumbar support adjustment control unit. The lumbar support adjustment control unit controls the corresponding inflation or deflation of the air cushions via integrated valves. The lumbar support pneumatic pump is directly actuated by the lumbar support adjustment control unit for the compressed air supply.