GM Service Manual Online
For 1990-2009 cars only

Lumbar Support Does Not Move In or Out w/o A45

Step

Action

Yes

No

Schematic Reference: Driver Seat Schematics or Passenger Seat Schematics

Connector End View Reference: Power Seat Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step  2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Verify that the Lumbar Support Does Not Move In or Out complaint is present.

Does the lumbar support system operate as described in the system description and operation?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step  3

3

  1. Probe the lumbar motor rearward control circuit of the lumbar horizontal motor with a test lamp that is connected to ground.
  2. Operate the lumbar motor REARWARD switch.

Does the test lamp illuminate?

Go to Step  4

Go to Step 6

4

  1. Probe the lumbar motor forward control circuit of the lumbar horizontal motor with a test lamp that is connected to ground.
  2. Operate the lumbar motor FORWARD switch.

Does the test lamp illuminate?

Go to Step 5

Go to Step 7

5

  1. Disconnect the lumbar horizontal motor harness connector.
  2. Connect a test lamp between the lumbar motor forward control circuit and the lumbar motor rearward control circuit of the harness connector.
  3. Operate the lumbar motor switch in the FORWARD and REARWARD directions.

Does the test lamp illuminate in both directions?

Go to Step 9

Go to Step 8

6

Test the lumbar motor rearward control circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 8

7

Test the lumbar motor forward control circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 8

8

Inspect for poor connections at the harness connector of the lumbar switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 10

9

Inspect for poor connections at the harness connector of the lumbar horizontal motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 11

10

Replace the lumbar switch. Refer to Lumbar Switch Replacement .

Did you complete the replacement?

Go to Step 12

--

11

Replace the lumbar horizontal motor. Refer to Front Seat Lumbar Support Replacement .

Did you complete the replacement?

Go to Step 12

--

12

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2

Lumbar Support Does Not Move In or Out with A45

Step

Action

Yes

No

Schematic Reference: Driver Seat Schematics

Connector End View Reference: Power Seat Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Verify that the Lumbar Support Does Not Move In or Out complaint is present.

Does the lumbar support system operate as described in the system description and operation?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Seat Lumbar Forward parameter in the Memory Seat Module data list.
  4. Operate the lumbar FORWARD switch.

Does the Seat Lumbar Forward parameter change state?

Go to Step 4

Go to Step 6

4

  1. With a scan tool, observe the Seat Lumbar Rearward parameter.
  2. Operate the lumbar REARWARD switch.

Does the Seat Lumbar Rearward parameter change state?

Go to Step 5

Go to Step 7

5

  1. Disconnect the lumbar horizontal motor harness connector.
  2. Connect a test lamp between the lumbar motor forward control circuit and the lumbar motor rearward control circuit of the harness connector.
  3. Operate the lumbar switch in the FORWARD and REARWARD directions.

Did the test lamp illuminate in both directions?

Go to Step 14

Go to Step 8

6

  1. Disconnect the lumbar switch harness connector.
  2. Connect a 3-amp fused jumper wire from battery positive voltage to the lumbar forward switch signal circuit of the harness connector.
  3. With a scan tool, observe the Seat Lumbar Forward parameter.

Does the Seat Lumbar Forward parameter change state?

Go to Step 13

Go to Step 10

7

  1. Disconnect the lumbar switch harness connector.
  2. Connect a 3-amp fused jumper wire from battery positive voltage to the lumbar rearward switch signal circuit of the harness connector.
  3. With a scan tool, observe the Seat Lumbar Rearward parameter.

Does the Seat Lumbar Rearward parameter change state?

Go to Step 13

Go to Step 11

8

Test the lumbar motor forward control circuit between the memory seat module (MSM) and the lumbar horizontal motor for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 9

9

Test the lumbar motor rearward control circuit between the MSM and the lumbar horizontal motor for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 12

10

Test the lumbar forward switch signal circuit between the lumbar switch and the MSM for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 12

11

Test the lumbar rearward switch signal circuit between the lumbar switch and the MSM for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 12

12

Inspect for poor connections at the harness connector of the MSM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 15

13

Inspect for poor connections at the harness connector of the lumbar switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 16

14

Inspect for poor connections at the harness connector of the lumbar horizontal motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 17

15

Replace the MSM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 18

--

16

Replace the seat lumbar switch. Refer to Lumbar Switch Replacement .

Did you complete the replacement?

Go to Step 18

--

17

Replace the seat lumbar horizontal motor. Refer to Front Seat Lumbar Support Replacement .

Did you complete the replacement?

Go to Step 18

--

18

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2