The power lumbar switches are inputs to the memory seat module (MSM). The seat module supplies the switch assembly with a battery positive switch supply circuit and monitor the switch signal circuits. In an inactive state the switch signal circuits are floating and when a switch is pressed the signal circuit is closed to the switch power circuit within the lumbar switch assembly. When battery voltage is present on the switch signal circuit the seat module determines the switch status to be active.

The battery voltage must be between 9-16 volts.

A switch signal circuit to the MSM is active for more than 60 seconds.

The MSM will disable the power lumbar function.

The scan tool may reference the Memory Seat Module as the Driver Seat Module.

Schematic Reference

Driver Seat Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the scan tool Driver Seat Module lumbar switch parameter while operating the lumbar switch in both directions. The reading should change between Idle, Forward, and Rearward.

1. Ignition OFF, disconnect the harness connector at the lumbar adjuster switch.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal E and ground.

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

3. Verify the scan tool Lumbar Switches parameter is Idle.

⇒	If not the specified value, test the appropriate signal circuit listed below for a short to voltage. If the circuit tests normal, replace the MSM.

•	Lumbar forward terminal A

•	Lumbar rearward terminal D

4. Install a 3A fused jumper wire between the appropriate signal circuit listed below and the B+ circuit terminal E. Verify the scan tool Lumbar Switches parameter is Forward or Rearward.

•	Lumbar forward terminal A

•	Lumbar rearward terminal D

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

5. If all circuits test normal, test or replace the lumbar adjuster switch.

Seat Adjuster Switch Test

1. Ignition OFF, disconnect the harness connector at the lumbar adjuster switch.
2. Test for infinite resistance between each seat direction signal terminal listed below and the B+ terminal E with the switch in the open position.

•	Lumbar forward switch terminal A

•	Lumbar rearward switch terminal D

⇒	If not the specified value, replace the lumbar adjuster switch.

3. Test for less than 1 ohm between each seat direction signal terminal listed below and the B+ terminal E with the switch in the closed position.

•	Lumbar forward switch terminal A

•	Lumbar rearward switch terminal D

⇒	If greater than the specified range, replace the lumbar adjuster switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.