Battery voltage, through the DRVR and PASS HTD SEAT 20 A fuses located in the I/P fuse block, is supplied at all times to the driver and passenger lumbar pump/control modules and the lumbar switches. When either the lumbar or seat bolster switch is pressed to inflate the lumbar support, battery voltage is applied through the switch contacts and the inflate control circuit to the lumbar pump/control module. In response to this signal, the module energizes its internal inflate relay and the pump motor runs to inflate the appropriate support bladder in the seat backrest until the switch is released. When the switch is pressed to deflate the lumbar support, battery voltage is applied through the switch contacts and the deflate control circuit to the lumbar pump/control module. The module energizes its internal deflate relay and air is released from the bladder until the switch is released. Ground for the driver seat pump/control module is supplied at ground G301 and the passenger seat pump/control module is supplied at ground G302.

Schematic Reference

Connector End View Reference

Component Connector End Views

Description and Operation

Lumbar Support Description and Operation

Electrical Information Reference

1. Ignition ON, press the appropriate seat lumbar INFLATE adjuster switch. The lumbar pump motor should run and the lumbar support should inflate and stay inflated until the deflate switch is pressed.
2. Press the lumbar DEFLATE adjuster switch to the deflate position. The lumbar support should deflate until the switch is released.
3. Press the seat bolster INFLATE adjuster switch. The lumbar pump motor should run and the seat back side bolsters should inflate and stay inflated until the deflate switch is pressed.
4. Press the seat bolster DEFLATE adjuster switch. The seat back side bolsters should deflate until the switch is released.

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

•	Driver seat lumbar switch terminal 5

•	Passenger seat lumbar switch terminal 3

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

3. Ignition OFF, connect the harness connector at the lumbar switch and disconnect the harness connector at the seat pump/control module.
4. Test for less than 5.0 Ω between the ground circuit terminal A and ground.

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

5. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal K and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

6. Connect a test lamp between the appropriate inflate control circuit terminal listed below and ground:

•	Lumbar inflate control terminal H

•	Seat backrest bolster inflate control terminal F

7. Ignition ON, press and release the appropriate inflate switch. The test lamp should turn ON and OFF as the switch is pressed and released.

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

⇒	If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the lumbar switch.

8. Connect a test lamp between the appropriate deflate control circuit terminal listed below and ground:

•	Lumbar deflate control terminal C

•	Seat backrest bolster deflate control terminal E

9. Ignition ON, press and release the appropriate deflate switch. The test lamp should turn ON and OFF as the switch is pressed and released.

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

⇒	If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the lumbar switch.

10. If all circuits test normal, replace the lumbar pump/control module.

Driver Seat Lumbar Switch

1. Ignition OFF, disconnect the harness connector at the driver seat lumbar switch.
2. Test for infinite resistance between the B+ terminal 5 and the switch terminals listed below with the switch in the open position:

•	Bolster inflate terminal 6

•	Bolster deflate terminal 3

•	Lumbar inflate terminal 7

•	Lumbar deflate terminal 4

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

3. Test for less than 1 Ω between the B+ terminal 5 and the switch terminals listed below with the appropriate switch in the closed position:

•	Bolster inflate terminal 6

•	Bolster deflate terminal 3

•	Lumbar inflate terminal 7

•	Lumbar deflate terminal 4

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

Passenger Seat Lumbar Switch

1. Ignition OFF, disconnect the harness connector at the passenger seat lumbar switch.
2. Test for infinite resistance between the B+ terminal 3 and the switch terminals listed below with the switch in the open position:

•	Bolster inflate terminal 1

•	Bolster deflate terminal 4

•	Lumbar inflate terminal 2

•	Lumbar deflate terminal 7

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

3. Test for less than 1 Ω between the B+ terminal 3 and the switch terminals listed below with the appropriate switch in the closed position:

•	Bolster inflate terminal 1

•	Bolster deflate terminal 4

•	Lumbar inflate terminal 2

•	Lumbar deflate terminal 7

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.