Power Seat Inoperative

Power Seat Inoperative

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.

Circuit/System Description

The power seats are controlled through the power seat switch. Battery voltage is supplied to the power seat switch through the SEATSW 40A fuse in the underhood BEC and the Power Seats 20A circuit breaker in the driver seat wiring harness. While the seat adjuster switches are in an inactive state the switch contacts are closed to the power seat switch ground circuit. When a power seat switch is pressed to an active state the switch contact is closed to the battery voltage supply circuit. Each seat adjuster motor is controlled by the power seat switch through 2 motor control circuits. The seat adjuster motors are bidirectional and the direction of adjuster motor rotation is determined by which of the adjuster motor control circuits is switched to battery voltage while the other remains grounded.

Reference Information
Schematic Reference

* Driver Seat Schematics (Power Distribution Diagram Index)
* Passenger Seat Schematics (Power Distribution Diagram Index)

Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Power Seats System Description and Operation (Power Seats System Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)for Scan Tool Information

Circuit/System Testing

1. Disconnect the harness connector at the seat adjuster switch.
2. Test for less than 1 ohm of resistance between the ground circuit terminal H and ground.

• If greater than 1 ohm, test the ground circuit for an open/high resistance.

3. Verify that a test lamp illuminates between the B+ circuit terminal A 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 seat adjuster switch.
5. Disconnect the harness connector at the affected seat motor assembly.
6. Connect a test lamp between the motor control circuit terminals of the affected motor.
7. Verify that the test lamp illuminates while pressing the appropriate seat switch in both directions.

• If the test lamp does not illuminate for both directions, test the motor circuits for a short to ground or an open/high resistance. If the circuits test normal replace the seat adjuster switch.

8. If the circuits test normal replace the inoperative motor assembly.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Power Seat Switch Replacement (Power Seat Switch Replacement)
* Power Seat Adjuster Mechanism Replacement (Service and Repair)