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
Battery voltage is supplied at all times to the driver and passenger seat adjuster switches through the PWR SEATS MSM 30 A circuit breaker located in the I/P fuse block. When a seat adjuster switch is in an inactive state, the switch contacts are closed to the switch ground circuit.
All power seat adjuster 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 operate this way.
Reference Information
Schematic Reference
* Driver Seat Schematics (Driver Seat Schematics)
* Passenger Seat Schematics (Passenger Seat Schematics)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Power Seats System Description and Operation (Power Seats System)
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 Verification
Operate the seat adjuster switches for the seat directional motors listed below in both directions. The seat should move in the commanded directions.
* Seat horizontal motor
* Seat front vertical motor
* Seat rear vertical motor
If all power seat functions are inoperative, refer to the Seat Adjuster Switch Circuit Test.
If one or more of the seat adjuster motors operate, refer to the Seat Adjuster 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 1 Ohms between the ground circuit terminal H and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
• 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.
3. If all circuits test normal, test or replace the seat adjuster switch.
Seat Adjuster Motor Circuit Test
1. Ignition OFF, disconnect the harness connector at the seat adjuster motor assembly.
2. Connect a test lamp between the appropriate control circuits listed below:
* Seat horizontal motor terminal A and terminal B
* Seat front vertical motor terminal C and terminal D
* Seat rear vertical motor terminal E and terminal F
3. Ignition ON, command the appropriate 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 seat adjuster switch.
4. If all circuits test normal, replace the seat adjuster motor assembly.
Component Testing
Seat Adjuster Switch
1. Ignition OFF, disconnect the harness connector at the seat adjuster switch.
2. Test for infinite resistance between the B+ terminal E and the switch terminals listed below with the switch in the open position:
* Front vertical upward switch terminal B
* Front vertical downward switch terminal D
* Rear vertical upward switch terminal A
* Rear vertical downward switch terminal G
* Horizontal forward switch terminal C
* Horizontal rearward switch terminal F
• If not the specified value, replace the seat adjuster switch.
3. Test for less than 1 Ohms between the B+ terminal E and the switch terminals listed below with the appropriate switch in the closed position:
* Front vertical upward switch terminal B
* Front vertical downward switch terminal D
* Rear vertical upward switch terminal A
* Rear vertical downward switch terminal G
* Horizontal forward switch terminal C
* Horizontal rearward switch terminal F
• If greater than the specified range, replace the seat adjuster switch.
4. Test for less than 1 Ohms between the ground terminal H and the switch terminals listed below with the switch in the open position.
* Front vertical upward switch terminal B
* Front vertical downward switch terminal D
* Rear vertical upward switch terminal A
* Rear vertical downward switch terminal G
* Horizontal forward switch terminal C
* Horizontal rearward switch terminal F
• 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.
* Front Seat Adjuster Motor Replacement (Front Seat Adjuster Motor Replacement)
* Power Seat Switch Replacement (Power Seat Switch Replacement)