Lumbar Support Inoperative (With W2E)
Lumbar Support Inoperative (With W2E)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
Battery voltage is supplied at all times to the driver and passenger seat lumbar adjuster switches through 25 A circuit breakers located in the rear fuse block. When a lumbar switch is pressed to inflate the lumbar support, battery voltage is applied through the switch contacts and the inflate signal circuit to the seat lumbar adjuster valve. In response to this signal, the lumbar adjuster valve energizes its internal inflate solenoid and applies battery voltage through the seat lumbar/bolster pump control circuit to the pump. The pump runs to inflate the appropriate lumbar bladder 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 signal circuit to the lumbar adjuster valve. The valve energizes its internal deflate solenoid and air is released from the bladder until the switch is released. Ground for the lumbar adjuster valve and the seat lumbar/bolster pump is supplied at G200 for the driver seat and G201 for the passenger seat.
Reference Information
Schematic Reference
* Driver Seat Schematics Driver Seat Schematics
* Passenger Seat Schematics Passenger Seat Schematics
Connector End View Reference
Component Connector End Views A/C Compressor Clutch
Description and Operation
Lumbar Support Description and Operation (With Memory-A45) Lumbar Support (With Memory-A45)Lumbar Support Description and Operation (Without Memory-A45) Lumbar Support (Without Memory-A45)
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Circuit/System Verification
1. Ignition ON, press and hold the appropriate seat lumbar adjuster switch in the FORWARD direction. The lumbar/bolster pump should run and the lower lumbar bladder should start to inflate. After the lower lumbar inflates to approximately 50%, the upper lumbar bladder should start to inflate until both bladders are 100% inflated. The lower lumbar will reach 100% first.
2. Press the lumbar adjuster switch in the REARWARD direction. The upper and lower lumbar support bladders should deflate until the switch is released.
3. Press the lumbar adjuster switch in the UP direction. The lumbar/bolster pump should run and the upper lumbar support bladder should inflate and stay inflated until the deflate switch is pressed.
4. Press and hold the lumbar adjuster switch in the DOWN direction. The upper lumbar bladder should start to deflate while the lower lumbar bladder inflates until the upper lumbar is 100% deflated and the lower lumbar is 100% inflated.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate seat lumbar adjuster switch.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal G and ground.
• 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 adjuster switch and disconnect the harness connector at the lumbar adjuster valve.
4. Test for less than 5 ohms between the ground circuit terminal 5 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
5. Connect a test lamp between the signal circuit terminals listed below and ground:
* Lumbar up switch signal terminal 1
* Lumbar rearward switch signal terminal 2
* Lumbar down switch signal terminal 3
* Lumbar forward switch signal terminal 4
6. Ignition ON, press and release the appropriate lumbar switch. The test lamp should turn ON and OFF when changing between the commanded states.
• If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, test or replace the lumbar adjuster switch.
• If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the lumbar adjuster switch.
7. Ignition OFF, connect the harness connector at the lumbar adjuster valve and disconnect the harness connector at the seat lumbar/bolster pump.
8. Test for less than 5 ohms between the ground circuit terminal 3 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
9. Connect a test lamp between the control circuit terminal 1 and ground.
10. Ignition ON, command the lumbar/bolster pump ON and OFF using either one of the lumbar inflate switches. The test lamp should turn ON and OFF when changing between the commanded states.
• 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 adjuster valve.
• 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 adjuster valve.
11. If all circuits test normal, test or replace the seat lumbar/bolster pump.
Component Testing
Lumbar Adjuster Switch
1. Ignition OFF, disconnect the harness connector at the appropriate seat lumbar adjuster switch.
2. Test for infinite resistance between the B+ terminal G and each signal terminal with the switch in the open position.
• If not the specified value, replace the lumbar adjuster switch.
3. Test for less than 1 ohms between the B+ terminal G and each signal terminal with the appropriate switch in the closed position.
• If greater than the specified range, replace the lumbar adjuster switch.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Driver Seat Lumbar Control Switch Replacement Service and Repair
* Passenger Seat Lumbar Control Switch Replacement Service and Repair
* Front Seat Lumbar Support Bladder Replacement (W2E) Service and Repair
* Driver or Passenger Seat Cushion Air Pump Replacement (W2E) Driver or Passenger Seat Cushion Air Pump Replacement (W2E)