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.

Schematic Reference

Driver Seat Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Lumbar Support Description and Operation

Electrical Information Reference

1. Ignition OFF, disconnect the harness connector at the lumbar adjuster switch.
2. Test for less than 5 ohms between the ground circuit terminal A and ground.

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

3. Test for less than 5 ohms between the ground circuit terminal C 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 D and ground.

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

5. Ignition OFF, connect the harness connector at lumbar adjuster switch and disconnect the harness connector at the lumbar motor.
6. Connect a test lamp between control circuit terminal 1 and control circuit terminal 2.
7. Verify the test lamp illuminates while pressing the lumbar adjuster switch in both directions.

⇒	If the test lamp does not illuminate for both directions, test the control circuits for a short to ground or an open/high resistance. If the circuits test normal, test or replace the lumbar switch.

8. If all circuits test normal, test or replace the lumbar motor.

Lumbar Adjuster Switch

1. Ignition OFF, disconnect the harness connector at the lumbar adjuster switch.
2. Test for infinite resistance between the control terminals listed below and the B+ terminal D with the switch in the open position.

•	Lumbar horizontal forward terminal E

•	Lumbar horizontal rearward terminal B

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

3. Test for less than 2 ohms between the control terminals listed below and the B+ terminal D with the switch in the closed position.

•	Lumbar horizontal forward terminal E

•	Lumbar horizontal rearward terminal B

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

4. Test for less than 2 ohms between control terminal B and the ground terminal A with the switch in the open position.

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

5. Test for less than 2 ohms between control terminal E and the ground terminal C with the switch in the open position.

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

Lumbar Motor

1. Ignition OFF, disconnect the harness connector at the lumbar motor.

Important: When performing the following tests, make sure that the lumbar is not already in the position the test is attempting to produce.

2. Install a 30A fused jumper wire between the control terminal 1 and 12 volts. Momentarily install a jumper wire between the control terminal 2 and ground. The lumbar motor should momentarily perform the FORWARD function.

⇒	If the function does not perform as specified, replace the lumbar motor.

3. Reverse the polarity of jumper wires; the a lumbar motor should perform the REARWARD function.

⇒	If the function does not perform as specified, replace the lumbar motor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.