Lumbar Supports

The lumbar seats is part of the W01 seating package which comes with a combination of the lumbar support (AL2) and seat heat (KA1).

Without Memory (A43)
The LH and RH power lumbar support system each consists of the lumbar switch and two reversible motors (lumbar in/out and lumbar up/down) which operate independently of each other.

The lumbar switch, located on each seat, directly controls the motors located in the seatback. Power for both seats is provided through the PWR SEAT circuit breaker in the rear junction block. Each motor contains its own electronic circuit breaker (PTC) which will trip at the end of travel. It resets only after voltage is removed from the motor.

When the lumbar switch is pushed to the IN position, battery positive voltage (B+) is applied via the in switch contacts to the lumbar in/out motor. The motor is grounded via the lumbar out switch contacts to ground. The motor runs to drive the lumbar support in away from the occupant's back until the switch is released or the end of travel is reached. The OUT position works similar to the IN position except that the voltage polarity is reversed causing the motor to run in the opposite direction driving the lumbar support out toward the occupant's back.

The lumbar up/down motor works in a similar way when the lumbar switch is operated in the up and down direction.

With Memory (A43)
The memory lumbar support system on the left band seat consists of the Memory Seat Module (MSM) and motors for the lumbar support with a position sensor attached to each motor. The MSM controls the movement of the two lumbar support motors. The motors operate independently of each other. The two lumbar support motors are the lumbar up/down motor and lumbar in/out motor.