Lumbar Massage Inoperative

Lumbar Massage Inoperative

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview






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.

Diagnostic Aids

The MSM is referenced in the Tech 2 as the driver position module (DPM).

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. Using a scan tool verify the Massage 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.

2. Ignition OFF, disconnect the harness connector at the lumbar massage switch.
3. Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal C and ground.

• If the test lamp does not illuminate, test the supply voltage for an open/high resistance.

4. Install a 3-amp fused jumper wire between the voltage supply circuit terminal C and the signal circuit terminal A. Verify the Massage Switch parameter is Active.

• If not Active, 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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Lumbar Switch Replacement - Front
* Control Module References for MSM replacement, programming and setup. Programming and Relearning Verification Tests