Power Seat Malfunction (Without Memory)
Power Seat Malfunction (Without Memory)
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
The driver seat without memory and the passenger seat are completely controlled through their respective seat switch. Battery voltage is supplied at all times to the seat switch through a 30 A fuse located in the Underhood fuse block. When the seat switches are in an inactive state, the switch contacts are closed to the ground circuit.
All seat motors are reversible. For example, when the seat horizontal forward switch is pressed to move the entire seat forward, ground is applied through the switch contacts and the seat horizontal motor forward control circuit to the motor. With the horizontal motor rearward switch contacts closed to the switch B+ circuit, 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 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
Driver Seat Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Power Seats System Description and Operation (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)
Circuit/System Testing
2 Way Power Seat
1. Ignition OFF, disconnect the harness connector at the S64D driver seat adjuster switch.
2. Test for less than 5 Ohms between the ground circuit terminals lister below and ground:
* Terminal A
* Terminal C
• 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 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. Ignition OFF, connect the harness connector at the S64D driver seat adjuster switch and disconnect the harness connector at the M57D driver seat vertical motor.
5. Connect a test lamp between control circuit terminal 1 and control circuit terminal 5.
6. 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 remains OFF for 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 S64D driver seat adjuster switch.
7. If all circuits test normal, test or replace the M57D driver seat vertical motor.
8 Way Power Seat
1. Ignition OFF, disconnect the harness connector at the S64D driver seat adjuster switch.
2. Test for less than 5 Ohms between the ground circuit terminal B 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 E and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. Ignition OFF, connector the harness connector at the S64D driver seat adjuster switch and disconnect the harness connector at the appropriate seat motor listed below:
* M51D seat horizontal motor
* M50D seat front vertical motor
* M55D seat rear vertical motor
* M56D seat recline motor
5. Connect a test lamp between control circuit terminal 1 and control circuit terminal 5.
6. Ignition ON, command the seat motor Up and Down or Forward and Rearward using the seat adjuster switch. The test lamp should turn ON when commanding the up and down or forward and rearward states.
• If the test lamp remains OFF for 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 S64D driver seat adjuster switch.
7. If all circuits test normal, test or replace the seat motor.
Component Testing
Seat Motor
1. Ignition OFF, disconnect the harness connector at the appropriate seat motor listed below:
* M51D seat horizontal motor
* M50D seat front vertical motor
* M55D seat rear vertical motor
* M56D seat recline 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 5 and ground. The seat motor should momentarily perform the appropriate FORWARD/REARWARD/UP/DOWN function.
• If the function does not perform as specified, replace the seat motor.
3. Reverse the polarity of jumper wires. The a seat motor should perform in the opposite direction.
• If the function does not perform as specified, replace the seat motor.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Driver Seat Adjuster Switch Replacement (Driver Seat Adjuster Switch Replacement)
* Front Seat Tilt Adjuster Actuator Replacement (Front Seat Tilt Adjuster Actuator Replacement)
* Driver or Passenger Seat Adjuster Vertical Actuator Replacement (Service and Repair)
* Front Seat Adjuster Actuator Replacement (Front Seat Adjuster Actuator Replacement)
* Driver or Passenger Seat Recliner Actuator Replacement (Driver or Passenger Seat Recliner Actuator Replacement)