The Sit-N-Lift mobility seat system is a dealer installed RPA and interfaces
with other vehicle systems in order to ensure safe operation. The seat may only be
operated while the vehicle is in park and the RR side door is open. The seat will
operate while the ignition is off or on and with the engine running, but anytime the
seat is not in the facing forward locked position the vehicle can not be shifted out
of the park position. Power and ground is supplied to the mobility seat system from
the passenger power seat at the body harness inline connector C314. The mobility seat
system uses a shift interlock relay controlled by the mobility seat control module
and is connected into the shift lock solenoid control circuit at the body control
module header connector C1. The mobility seat control module prevents
seat operation while the transmission selector lever is not in the park position.
The park signal circuit is accessed by the interface wiring harness at the body control
module header connector C2. The interface connection to the RR sliding door jamb switch
signal circuit is at the switch in the right C pillar. The door jamb switch signal
circuit is an input to the mobility seat control module and is used to prevent seat
operation while the RR sliding door is closed. The door jamb switch signal circuit
is also used for entering and exiting the diagnostic mode. Power to the hand held
remote is supplied through the door switch relay which is controlled by the door jamb
switch signal circuit. During seat operation the mobility seat module uses inputs
from 4 limit switches in order to determine the seat position. The limit switch signal
circuits are referenced from battery voltage within the module. The limit switches
will open or close the switch signal circuits to ground in order for the module to
determine them to be active or inactive. The mobility seat module also monitors an
input from a hall effect sensor in the rotation motor for object detection while the
seat is being rotated in or out. The hall effect is a 12 volt 3 wire sensor and the
signal circuit is referenced from battery voltage within the module.
Rotational movement is controlled by the module using the swivel in and swivel
out limit switches while lift movement is controlled using the lift upper and lift
lower limit switches. When the seat is in the forward facing position the swivel in
and lift upper limit switches will be in an active state. Both of these switches are
set up in such a way that when contact is made against the lever the switch contacts
will open. When rotate out movement is started pressure against the swivel in limit
switch lever will be released and the switch contacts close. During rotation operation
the swivel in and swivel out limit switches will be inactive. The control module determines
rotation out movement is complete when contact is made against the lever of the swivel
out limit switch and the signal becomes active. The swivel out and lift lower limit
switches are considered active when the switch contacts are closed. When the rotation
out movement is complete and the control module begins lift lower operation, pressure
against the lift upper limit switch lever is released and the switch contacts close.
During lift operation the lift upper and lift lower limit switches will be inactive.
The control module determines lift lower operation to be complete when contact is
made against the lever of the lift lower limit switch and the switch contacts close.
Active Switch States
• | Swivel In Limit Switch - Open |
• | Swivel Out Limit Switch - Closed |
• | Lift Upper Limit Switch - Open |
• | Lift Lower Limit Switch - Closed |