For 1990-2009 cars

## Power Seat Inoperative 4-Way

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Seat Adjuster Switch B+ | 1 | 1 | -- | --
Front Vertical Motor Down Control | 1 | 1 | -- | --
Front Vertical Motor Up Control | 1 | 1 | -- | --
Rear Vertical Motor Down Control | 1 | 1 | -- | --
Rear Vertical Motor Up Control | 1 | 1 | -- | --
Seat Adjuster Switch Ground | -- | 1 | -- | --
1. Power seat inoperative

### Circuit/System Description

The power seat is controlled through the seat adjuster switch. Battery voltage is supplied at all times to the seat adjuster switch through the Power Seats 20 A Circuit Breaker located in the instrument panel fuse block. When the seat adjuster switches are in an inactive state, the switch contacts are closed to the switch ground circuit.

Both seat motors are reversible. For example, when the seat front vertical up switch is pressed to move the front of the seat up, battery voltage is applied through the switch contacts and the front vertical motor up control circuit to the motor. The motor is grounded through the seat front vertical motor down switch contacts and the front vertical motor down control circuit to the motor. The motor runs in order to drive the front of the seat upward until the switch is released. Moving the front of the seat downward works similarly to moving the seat upward, except that battery positive voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction. The seat rear vertical motor is also powered this way.

### Reference Information

#### Schematic Reference

Driver Seat Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Power Seats System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

### Circuit/System Verification

Operate the seat switches for the seat motors listed below in both directions. The seat should move in the commanded directions.

• | Front vertical motor

• | Rear vertical motor

⇒ | If the power seat is inoperative in all directions, refer to the Seat Adjuster Switch Circuit Test.

⇒ | If either one of the seat motors operate, refer to the Seat Motor Circuit Test.

### Circuit/System Testing

#### Seat Adjuster Switch Circuit Test

1. Ignition OFF, disconnect the harness connector at the appropriate seat adjuster switch.
2. Test for less than 5 Ω between the ground circuit terminal 2 and ground.

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

3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 1 and ground.

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

4. If all circuits test normal, test or replace the seat adjuster switch.

#### Seat Motor Circuit Test

1. Ignition OFF, disconnect the harness connector at the appropriate seat motor.
2. Connect a test lamp between control circuit terminal 1 and control circuit terminal 2.
3. Ignition ON, command the seat motor Up and Down using the seat adjuster switch. The test lamp should turn ON when commanding the up and down states.

⇒ | If the test lamp is always OFF during either of the commands, test the control circuits for a short to ground or an open/high resistance. If the circuits test normal, test or replace the seat adjuster switch.

4. If all circuits tests normal, test or replace the seat motor.

### Component Testing

#### Seat Adjuster Switch Test

1. Ignition OFF, disconnect the harness connector at the seat adjuster switch.
2. Test for infinite resistance between the B+ terminal 1 and each control terminal listed below with the switch in the open position.

• | Seat front up terminal 3

• | Seat front down terminal 4

• | Seat rear up terminal 5

• | Seat rear down terminal 6

⇒ | If not the specified value, replace the seat adjuster switch.

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

• | Seat front up terminal 3

• | Seat front down terminal 4

• | Seat rear up terminal 5

• | Seat rear down terminal 6

⇒ | If greater than the specified range, replace the seat adjuster switch.

4. Test for less than 1 Ω between the ground terminal 2 and each control terminal listed below with the switch in the open position.

• | Seat front up terminal 3

• | Seat front down terminal 4

• | Seat rear up terminal 5

• | Seat rear down terminal 6

⇒ | If greater than the specified range, replace the seat adjuster switch.

#### Seat Motors

1. Ignition OFF, disconnect the harness connector at the appropriate seat motor.

Note: When performing the following tests, make sure that the seat is not already in the position the test is attempting to produce.

2. Install a 30 A fused jumper wire between control terminal 1 and 12 V. Momentarily install a jumper wire between control terminal 2 and ground. The seat motor should operate in the UP direction.

⇒ | If the motor does not perform as specified, replace the seat motor.

3. Reverse the jumper wires. The seat motor should operate in the DOWN direction.

⇒ | If the motor does not perform as specified, replace the seat motor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Power Seat Switch Replacement

• | Seat Adjuster Motor Replacement - Vertical