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.

Schematic Reference

Rear Seat Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Sit-N-Lift Mobility Seat Description and Operation

Electrical Information Reference

1. Ignition ON, verify the door ajar indicator turns ON and OFF while opening and closing the right rear sliding door.

⇒	If the door ajar indicator does not operate as specified, refer to Door Ajar Indicator Malfunction .

2. Open the right rear sliding door. Press the door ajar switch 5 times within 4 seconds. Verify the sit-n-lift seat module enters diagnostic mode.

⇒	If the sit-n-lift seat does not enter diagnostic mode, refer to Sit-N-Lift Mobility Seat Does Not Enter Diagnostic Mode

3. With the vehicle in diagnostic mode, verify only DTC 11 is flashing.

⇒	If any other DTC is flashing, refer to Diagnostic Trouble Code (DTC) List - Vehicle

4. Place the transmission shift lever in the park position. With a scan tool, verify the PRNDL-Park parameter is ON.

⇒	If other than specified value, refer to Transmission Control Lever Malfunction

5. Open the right rear sliding door. Attempt to turn on the hand held remote by pressing the red power button. Verify the red LED illuminates.

⇒	If the LED does not illuminate, refer to Hand Held Remote Malfunction.

⇒	If the LED illuminates, refer to Sit-n-Lift Seat Malfunction.

Hand-held Remote Malfunction

1. Ignition OFF, disconnect the X2 harness connector at the sit-n-lift seat module.
2. Right rear sliding door closed, test for infinite resistance between the signal circuit terminal 12 and ground.

⇒	If less than the specified value, test the signal circuit for a short to ground.

3. Right rear sliding door open, test for less than 10 ohms between the signal circuit terminal 12 and ground.

⇒	If greater than the specified range, test the signal circuit for a short to ground.

4. Connect the X2 harness connector. Disconnect the Sit-N-Lift Seat/Door Jamb Switch Relay.
5. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

6. Verify that a test lamp illuminates between the B+ circuit terminal 5 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

7. Connect the Sit-N-Lift Seat/Door Jamb Switch Relay. Disconnect the Sit-N-Lift Seat Remote. Open the right rear sliding door.
8. Verify that a test lamp illuminates between the B+ circuit terminal 1 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit test normal, test or replace the Sit-N-Lift Seat/Door Jamb Switch Relay.

9. Test for less than 1 ohm of resistance between the ground circuit terminal 5 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

10. If all circuits test normal, replace the sit-n-lift Seat Remote.

Sit-n-Lift Seat Malfunction

1. Ignition OFF, disconnect the X1 harness connector at the sit-n-lift seat module.
2. Test for less than 1 ohm of resistance between the ground circuit terminal 4 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. Test for less than 1 ohm of resistance between the ground circuit terminal 3 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

4. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 12 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

5. Verify that a test lamp illuminates between the B+ circuit terminal 8 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

6. Ignition OFF, connect the X1 harness connector. Disconnect the Sit-N-Lift Ignition Relay.
7. Test for less than 1 ohm of resistance between the ground circuit terminal 1 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

8. Test for less than 1 ohm of resistance between the ground circuit terminal 3 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

9. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and ground circuit terminal 1.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

10. With the transmission lever in the park position, test for B+ on the signal circuit terminal 7.

⇒	If not the specified value, test the signal circuit for a short to ground or an open/high resistance.

11. Ignition OFF, connect the Sit-N-Lift Ignition Relay. Turn the ignition ON, verify the relay clicks.

⇒	If the relay does not click, test or replace the Sit-N-Lift Ignition Relay.

12. Ignition OFF, disconnect the X2 harness connector at the sit-n-lift seat module.
13. Ignition ON, test for less than 1 ohm of resistance between the signal circuit terminal 11 and ground.

⇒	If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit test normal, test or replace the Sit-N-Lift Ignition Relay.

14. With the transmission lever in the park position, test for B+ on the signal circuit terminal 18.

⇒	If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit test normal, test or replace the Sit-N-Lift Ignition Relay.

15. Press the DOWN button on the seat remote. Test for B+ on the signal circuit terminal 9.

⇒	If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit test normal, test or replace the Sit-N-Lift Seat Remote.

16. Press the UP button on the seat remote. Test for B+ on the signal circuit terminal 20.

⇒	If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit test normal, test or replace the Sit-N-Lift Seat Remote.

17. If all circuits test normal, replace the Sit-N-Lift Seat Module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.