Power Seat Inoperative

Power Seat Inoperative

Diagnostic Instructions

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

Circuit/System Description

The Power seat system is completely controlled through the seat adjuster switch. Battery voltage is supplied at all times to the seat adjuster switch from the PWR SEAT 60A circuit breaker that is located in the underhood fuse block. When the seat adjuster switches are in an inactive state, the switch contacts are closed to the switch ground circuit.

All seat motors are reversible. For example, when the seat horizontal forward switch is pressed to move the entire seat forward, battery voltage is applied through the switch contacts and the seat horizontal motor forward control circuit to the motor. The motor is grounded through the horizontal motor rearward switch contacts and the horizontal motor rearward control circuit to the motor. The motor runs in order to drive the entire seat forward until the switch is released. Moving the entire seat rearward works similarly to moving the entire seat forward, except that battery positive voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction. All seat motors are powered this way.

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 C 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 F 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 inoperative seat motor.
6. Connect a test lamp between the motor control circuit terminals of the inoperative motor.
7. Verify that the test lamp illuminates while pressing and releasing the related seat switch in both directions. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the controls circuits a short to voltage. If the circuits test normal, test or replace the seat adjuster switch.
• If the test lamp remains OFF during either of the commands, test the for a short to ground or an open/high resistance on either control circuit. If the circuits test normal, test or replace the seat adjuster switch.

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

Repair Instructions

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