Power Seat Inoperative (Without Memory A45)
Power Seat 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 without memory is completely controlled through the seat adjuster switch. Battery voltage is supplied at all times to the seat adjuster switch from the 30A SEATS circuit breaker that is located in the rear fuse block. When the seat adjuster switches are in an inactive state, the switch contacts are closed to the switch ground circuit and G302.
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.
Reference Information
Schematic Reference
Passenger Seat Schematics (Passenger Seat Schematics)
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 (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning)for scan tool information
Circuit/System Verification
Operate the switches for the seat directional motors listed below in both directions. The seat should move in the commanded directions.
* Seat front vertical motor
* Seat rear vertical motor
* Seat horizontal motor
* Seat recline motor
If the power seat is inoperative in all directions, refer to the Seat Adjuster Switch Circuit Test.
If 1 or more of the seat adjuster motors operate, refer to the Seat Adjuster Motor Control Circuit Test.
Circuit/System Testing
Seat Adjuster Switch Circuit Test
1. Ignition OFF, disconnect the harness connector at the passenger seat adjuster switch.
2. Test for less than 5 ohms between the ground circuit terminal D 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 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. If all circuits test normal, test or replace the seat adjuster switch.
Seat Adjuster Motor Control Circuit Test
1. Ignition OFF, disconnect the harness connector at the appropriate seat motor.
2. Connect a test lamp between control circuit terminal A and control circuit terminal B.
3. Operate the appropriate seat switch in both directions. The test lamp should turn ON when commanding the motor in both directions.
• If the test lamp remains 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 test normal, test or replace the appropriate seat motor.
Component Testing
Seat Adjuster Switch
1. Ignition OFF, disconnect the harness connector at the passenger seat adjuster switch.
2. Test for infinite resistance between the B+ terminal A and each seat direction signal terminal listed below with the switch in the open position.
* Seat horizontal forward switch terminal C
* Seat horizontal rearward switch terminal B
* Seat front vertical upward switch terminal G
* Seat front vertical downward switch terminal F
* Seat rear vertical upward switch terminal J
* Seat rear vertical downward switch terminal H
* Seat recline forward switch terminal E
* Seat recline rearward switch terminal K
• If not the specified value, replace the seat adjuster switch.
3. Test for less than 1 ohm between the B+ terminal A and each seat direction signal terminal listed below with the switch in the closed position.
* Seat horizontal forward switch terminal C
* Seat horizontal rearward switch terminal B
* Seat front vertical upward switch terminal G
* Seat front vertical downward switch terminal F
* Seat rear vertical upward switch terminal J
* Seat rear vertical downward switch terminal H
* Seat recline forward switch terminal E
* Seat recline rearward switch terminal K
• If greater than the specified range, replace the seat adjuster switch.
4. Test for less than 1 ohm between the ground terminal D and each seat direction signal terminal listed below with the switch in the open position.
* Seat horizontal forward switch terminal C
* Seat horizontal rearward switch terminal B
* Seat front vertical upward switch terminal G
* Seat front vertical downward switch terminal F
* Seat rear vertical upward switch terminal J
* Seat rear vertical downward switch terminal H
* Seat recline forward switch terminal E
* Seat recline rearward switch terminal K
• If greater than the specified range, replace the seat adjuster switch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Power Seat Switch Replacement (Power Seat Switch Replacement)
* Front Seat Lumbar Control Switch Replacement (Front Seat Lumbar Control Switch Replacement)
* Power Seat Adjuster Mechanism Replacement (Power Seat Adjuster Mechanism Replacement)
* Front Seat Lumbar Support Replacement (Front Seat Lumbar Support Replacement)