Power Seat Inoperative (A45)
Power Seat Inoperative (A45)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
Battery positive voltage is supplied to the seat adjuster switch from the memory seat module (MSM). When a seat adjustment switch is operated, battery voltage is applied through the switch contacts to the appropriate switch signal circuit to the MSM. The MSM responds to the input from the adjuster switch by commanding the selected seat motor to move in response to the switch signal. When a memory recall switch is pressed, ground is applied through the switch contacts and the switch signal circuit to the memory seat module (MSM). The MSM then commands the appropriate seat motors to move to the pre-recorded seat position stored in memory in response to the switch signal.
All motors are reversible. For example, when the seat switch is operated to moved the entire seat forward, battery positive voltage is applied through the horizontal forward switch contacts and the power seat horizontal forward switch signal circuit to the MSM. In response to this signal, the MSM applies battery positive voltage through the driver seat horizontal motor forward control circuit to the horizontal motor. The MSM supplies ground to the motor through the driver seat horizontal motor rearward control circuit. The motor runs 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 the opposite circuits causing the motor to run in the opposite direction. All other seat motors are also powered this way.
Reference Information
Schematic Reference
Driver Seat Schematics (Driver 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)
* Memory Seats Description and Operation (Memory Seats Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning)for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the X1 harness connector at the MSM.
2. Ignition OFF, test for less than 5 ohms of resistance between the ground circuit terminal B and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the MSM.
3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal C and ground.
• If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
4. Ignition OFF, connect the X1 harness connector at the MSM. Disconnect the harness connector at the power seat switch.
5. 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. If the circuit test normal test or replace the MSM.
6. Verify the scan tool seat switch parameters display Inactive for all switches.
• If the scan tool displays Forward, Back or Invalid, test the appropriate switch signal circuit for a short to voltage. If the circuit tests normal, replace the MSM.
7. Install a 3A fused jumper wire between the B+ circuit terminal A and the inoperative switch signal circuit. Verify the appropriate scan tool seat switch parameter is Forward or Back.
• If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the MSM.
8. If all circuits test normal, test or replace the power seat switch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Driver Seat Adjuster Memory Switch Replacement (Service and Repair)
* Power Seat Switch Replacement (Power Seat Switch Replacement)
* Control Module References (Programming and Relearning)for MSM replacement, setup, and programming