Lumbar Massage Inoperative

LUMBAR MASSAGE INOPERATIVE




DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

CIRCUIT/SYSTEM DESCRIPTION
Battery positive voltage is supplied to the driver seat lumbar massage switch from the memory seat module (MSM) and to the passenger front seat from the MSM fuse. When the lumbar massage switch is pressed, battery voltage is applied through the switch contacts and the lumbar massage signal circuit to the MSM. The MSM then cycles battery voltage and ground through the lumbar vertical motor control circuits to the lumbar vertical motor for 10 minutes or until the massage function is canceled. The MSM supplies the lumbar vertical position sensor with a 5-volt reference and low reference circuits. When the motor rotates, the resistance of the potentiometer varies changing the voltage of the lumbar vertical position sensor signal to the MSM.

CIRCUIT/SYSTEM VERIFICATION
Ignition ON, use a scan tool to observe the Massage Switch parameter while pressing the massage switch. The reading should change between Inactive and Active.

CIRCUIT/SYSTEM TESTING
1. Ignition OFF, disconnect the harness connector at the lumbar massage switch.
2. Ignition ON, verify that a test lamp illuminates between the voltage supply circuit and ground.
- If the test lamp does not illuminate, test the supply voltage for an open/high resistance. If the circuit tests normal, replace the memory seat module.
3. Using a scan tool verify the Lumbar Switch parameter is Inactive. If not Inactive, test the signal circuit for a short to voltage. If the circuit tests normal, replace the memory seat module.
4. Install a 3-amp fused jumper wire between the signal circuit and the voltage supply circuit. Verify the Lumbar Switch parameter is Active.
- If not Pressed, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the memory seat module.
5. If all circuits tests normal, replace the lumbar massage switch.

COMPONENT TESTING

LUMBAR MASSAGE SWITCH
1. Ignition OFF, disconnect the harness connector at the lumbar massage switch.
2. Test for infinite resistance between the signal terminal and the supply voltage terminal with the switch in the open position.
- If less than infinite, replace the lumbar massage switch.
3. Test for less than 3 ohms between the signal terminal and the supply voltage terminal with the switch in the closed position.
- If greater than 3 ohms, replace the lumbar massage switch.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Lumbar Switch Replacement - Front
- Control Module References for memory seat module replacement, setup, and programming