Driver Power Seat Operation

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

As the seat is adjusted, the DSM monitors fluctuations of the motor current (ripple count for DC (direct current) motors) to determine the current seat position. The DSM removes voltage from the motor upon termination of the seat control switch input or if the DSM 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 DSM, 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.

DSM Hard Stop/Soft Stop 

A hard stop occurs when one of the memory seat track or backrest axes physically reach the end of travel and can go no further. A soft stop occurs when the seat stops before it physically reaches the end of travel. The hard stop is set by seat design and cannot be changed or adjusted. The soft stop is set by the DSM. The seat track axes are forward/rearward, front up/down and rear up/down. The backrest axis is recline forward/backward. If equipped with 24-way or 30-way seats, there are additional axes for the cushion extension (forward/rearward) and head restraint (forward/rearward and up/down). To prevent unnecessary stress on the seat and motors, the DSM sets soft stop positions, 2 for each axis of motion. The DSM uses a preset distance from the hard stop to determine where the soft stop occurs. When an axis reaches the hard stop and the switch is held for approximately one second, the DSM establishes the soft stop for that axis in that direction.

Easy Entry/Exit 

The easy entry/exit feature is a function of the DSM that moves the driver seat back approximately 50.8 mm (2 in) (unless seat is already positioned at or near the end of travel) when the ignition is turned off. The DSM receives ignition off status over the MS-CAN and operates the driver seat rearward. The DSM cancels this operation if the function is disabled or a valid input command is received from the driver seat control switch, memory set switch or exterior mirror control switch.

The DSM records the current seat positions before operating the seat for an easy exit operation. During easy entry operation (when the ignition is turned on), the seat is returned to the recorded seat position prior to the easy exit operation. Easy entry operation is cancelled if a valid input command is received by the DSM or a memory position recall using the memory set switch is received.

The easy entry/exit feature can be enabled/disabled through the message center. For information on programming vehicle settings in the message center, refer to the Owner's Literature.