GM Service Manual Online
For 1990-2009 cars only

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

Memory Switch Reference Voltage

1

1

--

--

Memory Switch Signal

1

1

1

--

1. Memory seat feature inoperative

Circuit/System Description

Reference voltage is supplied to the memory switch from the driver door module (DDM). When a memory switch is pressed, battery voltage is applied through the switch contacts, a series of resistors and thorough the memory switch signal circuit to the DDM. The DDM then sends a serial data message to the memory seat module (MSM) indicating the memory recall request. The MSM then commands the appropriate seat motors to move to the pre-recorded seat positions stored in memory in response to the switch input.

Diagnostic Aids

    • The scan tool references the driver door module (DDM) as the Driver Door Switch.
    • The scan tool may reference the memory seat module (MSM) as the Driver Position Module.

Reference Information

Schematic Reference

Driver Seat Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References

Circuit/System Verification

  1. Verify that all manual power seat and lumbar functions operate when being controlled by the seat adjuster and lumbar switches.
  2. If any seat or lumbar function does not operate, refer to Power Seat Inoperative or Lumbar Support Inoperative .
  3. Verify that the memory recall personalization option is ON. Refer to the owners manual.
  4. Verify that memory positions for driver 1 and driver 2 have been recorded to memory by observing the scan tool Driver Position Module, Memory Data 1 and Memory Data 2 parameters.

Circuit/System Testing

  1. Ignition ON, verify the scan tool Driver Door Switch Memory Recall Switches parameter is approximately 2.75 volts while pressing the memory 1 switch.
  2. If not the specified value, refer to the Memory Switch component test. If the memory switch tests normal, replace the driver door switch.
  3. Verify the scan tool Memory Recall Switches parameter is approximately 1.75 volts while pressing the memory 2 switch.
  4. If not the specified value, test or replace the memory switch.
  5. Verify the scan tool Memory Recall Switches parameter is approximately 1.0 volt while pressing the EXIT switch.
  6. If not the specified value, test or replace the memory switch.
  7. If all circuits test normal, replace the MSM.

Component Testing

Memory Switch

  1. Ignition OFF, disconnect the X4 harness connector at DDM.
  2. Test for infinite resistance between the signal circuit terminal 5 and the reference voltage circuit terminal 14 with the switch in the open position.
  3. If not the specified value, replace the memory switch.
  4. Test the resistance between terminal 5 and terminal 14 while pressing the memory 1, memory 2, and EXIT buttons. Compare the resistance readings to the values in the Memory Switch Values table below.
  5. If the resistance values are not within the specified range, replace the memory switch.

Switch Position

Resistance

Idle

Infinite

Memory 1

2.03K-2.49K Ω

Memory 2

3.83K-4.69K Ω

EXIT

9.32K-10.18K Ω

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Driver Seat Adjuster Memory Switch Replacement
    •  Control Module References for DDM or MSM replacement, setup, and programming