Lumbar Support Inoperative

Lumbar Support Inoperative

Circuit/System Description

B+ is supplied to the lumbar adjuster switch from the PWR SEAT circuit breaker. Ground is supplied to the lumbar adjuster switch from G301. When the lumbar adjuster switch is pressed to increase or decrease lumbar support, the lumbar adjuster switch provides voltage and ground to the appropriate terminals of the seat lumbar motor.


Reference Information
Schematic Reference

Driver Seat Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Lumbar Support Description and Operation (Lumbar Support Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Testing

1. Disconnect the lumbar adjuster switch.
2. Ignition ON, verify that a test lamp illuminates between the ground circuit terminal A and B+.

• If the test lamp does not illuminate, test the ground circuit for an open, high resistance, or short to voltage.

3. Verify that a test lamp illuminates between the ground circuit terminal C and B+.

• If the test lamp does not illuminate, test the ground circuit for an open, high resistance, or short to voltage.

4. Verify that a test lamp illuminates between the B+ circuit terminal D and ground.

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

5. Ignition OFF, reconnect the lumbar adjuster switch.
6. Disconnect the seat lumbar motor.
7. Ignition ON, connect a test lamp between the inflate circuit terminal 1 and ground.
8. Press and release the lumbar adjuster switch in the Inflate position. The test lamp should turn ON and OFF when pressing and releasing the switch.

• If the test lamp is always ON, test the circuit for a short to voltage. If the circuit tests normal, replace the lumbar adjuster switch.


• If the test lamp does not illuminate, test the circuit for an open, high resistance, or short to ground. If the circuit tests normal, replace the lumbar adjuster switch.

9. Connect a test lamp between the deflate circuit terminal 2 and ground.
10. Press and release the lumbar adjuster switch in the Deflate position. The test lamp should turn ON and OFF when pressing and releasing the switch.

• If the test lamp is always ON, test the circuit for a short to voltage. If the circuit tests normal, replace the lumbar adjuster switch.


• If the test lamp does not illuminate, test the circuit for an open, high resistance, or short to ground. If the circuit tests normal, replace the lumbar adjuster switch.

11. If all circuits test normal, replace the lumbar motor.



Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Lumbar Switch Replacement (Lumbar Switch Replacement)
* Front Seat Lumbar Support Replacement (Front Seat Lumbar Support Replacement)