Lumbar Support Inoperative (Without Memory A45)
Lumbar Support Inoperative (Without Memory A45)
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
Power seat lumbar support without memory is completely controlled through the seat lumbar adjuster switch. Battery voltage is supplied at all times to the seat lumbar adjuster switch from the RT/FRT/PWR/SEAT 25 A circuit breaker that is located in the rear fuse block. When the seat lumbar adjuster switches are in an inactive state, the switch contacts are closed to the switch ground circuit.
The lumbar motor is reversible. For example, when the lumbar horizontal forward switch is pressed to move the lumbar support forward, battery voltage is applied through the switch contacts and the lumbar motor forward control circuit to the motor. The motor is grounded through the lumbar motor rearward switch contacts and the lumbar motor rearward control circuit to the motor. The motor runs in order to drive the lumbar support forward toward the occupants back until the switch is released. Moving the lumbar support rearward works similarly to moving the lumbar support forward, except that battery positive voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction.
Reference Information
Schematic Reference
Passenger Seat Schematics Passenger Seat Schematics
Connector End View Reference
Component Connector End Views Connector Views
Description and Operation
Lumbar Support Description and Operation (Without Memory-A45) Lumbar Support (Without Memory-A45)Lumbar Support Description and Operation (With Memory-A45) Lumbar Support (With 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 Testing
1. Disconnect the harness connector at the lumbar adjuster switch.
2. Test for less than 1 Ohms between the ground circuit terminals listed below and ground:
* Terminal A
* Terminal C
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. 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.
4. Connect the harness connector at the lumbar adjuster switch and disconnect the harness connector at the lumbar motor.
5. Ignition ON, verify that a test lamp illuminates between control circuit terminal 1 and control circuit terminal 2 while pressing the lumbar switch in both directions.
• If the test lamp does not illuminate for either direction, test the control circuits for a short to ground or an open/high resistance. If the circuits test normal replace the lumbar adjuster switch.
6. If the circuits test normal replace the lumbar motor.
Component Testing
Lumbar Adjuster Switch
1. Ignition OFF, disconnect the harness connector at the lumbar adjuster switch.
2. Test for infinite resistance between each control terminal listed below and the B+ terminal D with the switch in the open position.
* Lumbar horizontal forward switch terminal B
* Lumbar horizontal rearward switch terminal E
• If not the specified value, replace the lumbar adjuster switch.
3. Test for less than 1 ohm between each control terminal listed below and the B+ terminal D with the switch in the closed position.
* Lumbar horizontal forward switch terminal B
* Lumbar horizontal rearward switch terminal E
• If greater than the specified range, replace the lumbar adjuster switch.
4. Test for less than 1 Ohms between each control terminal and the ground terminal listed below with the switch in the open position.
* Lumbar horizontal forward switch terminal B and terminal C
* Lumbar horizontal rearward switch terminal E and terminal A
• If greater than the specified range, replace the lumbar adjuster switch.
Lumbar Motor
1. Ignition OFF, disconnect the harness connector at the lumbar motor.
Note: When performing the following tests, make sure that the lumbar support is not already in the position the test is attempting to produce.
2. Install a 30 A fused jumper wire between the control terminal 1 and 12 V. 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 REARWARD function.
• If the function does not perform as specified, replace the lumbar motor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Driver Seat Lumbar Control Switch Replacement (AQ9) Driver Seat Lumbar Control Switch Replacement (AQ9)Driver Seat Lumbar Control Switch Replacement (W2E) Driver Seat Lumbar Control Switch Replacement (W2E)
* Passenger Seat Lumbar Control Switch Replacement (AQ9) Passenger Seat Lumbar Control Switch Replacement (AQ9)Passenger Seat Lumbar Control Switch Replacement (W2E) Passenger Seat Lumbar Control Switch Replacement (W2E)
* Seat Lumbar Sub System Replacement (AQ9) Seat Lumbar Sub System Replacement (AQ9)Seat Lumbar Sub System Replacement (W2E) Seat Lumbar Sub System Replacement (W2E)