Passenger Power Seat Operation

The passenger seat control switch communicates over a LIN to the SCMB. When the SCMB receives the input from the seat control switch, the SCMB provides power to the appropriate seat motor until the input is removed. The motor circuits are normally grounded through the SCMB. The SCMB internally switches the appropriate circuit from ground to voltage to operate the motors.

As the seat is adjusted, the SCMB monitors fluctuations of the motor current (ripple count for DC (direct current) motors) to determine the current seat position. The SCMB removes voltage from the motor upon termination of the seat control switch input or if the SCMB does not detect movement from the motor.

If equipped with 4-way lumbar, the front seat power lumbar assembly contains 2 inflatable air bladders. Depending upon the voltage signals received from the SCMB, the power lumbar assembly either activates the air pump while diverting air to inflate the selected bladder, or it deflates the selected bladder by venting it to the atmosphere.