GM Service Manual Online
For 1990-2009 cars only

Lumbar Support Does Not Move Up or Down w/o A45

Step

Action

Yes

No

Schematic Reference: Lumbar Support Schematics

Connector End View Reference: Power Seat Connector End Views

1

Did you review the power seat system operation and perform the necessary inspection?

Go to Step 2

Go to Symptoms - Seats

2

Verify that the Lumbar Support Does Not Move Up or Down 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 up control circuit of the lumbar vertical motor with a test lamp that is connected to a good ground.
  2. Operate the lumbar motor UP adjuster switch.

Does the test lamp illuminate?

Go to Step  4

Go to Step 6

4

  1. Probe the lumbar motor down control circuit of the lumbar vertical motor with a test lamp that is connected to a good ground.
  2. Operate the lumbar motor DOWN adjuster switch.

Does the test lamp illuminate?

Go to Step 5

Go to Step 7

5

  1. Disconnect the lumbar vertical motor harness connector.
  2. Connect a test lamp between the lumbar motor up control circuit and the lumbar motor down control circuit of the motor harness connector.
  3. Operate the lumbar motor adjuster switch in the UP and DOWN directions.

Does the test lamp illuminate in both directions?

Go to Step 9

Go to Step 8

6

Test the lumbar motor up 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 down 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 adjuster 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 vertical 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 adjuster switch. Refer to Lumbar Switch Replacement .

Did you complete the replacement?

Go to Step 12

--

11

Replace the lumbar vertical 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 Up or Down with A45

Step

Action

Yes

No

Schematic Reference: Lumbar Support Schematics

Connector End View Reference: Power Seat Connector End Views

1

Did you perform the Diagnostic System Check - Power Seats Systems?

Go to Step 2

Go to Diagnostic System Check - Power Seat Systems

2

Verify that the Lumbar Support Does Not Move Up or Down 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 Up parameter in the Memory Seat Module data list.
  4. Operate the lumbar UP switch.

Does the Seat Lumbar Up parameter change state?

Go to Step 4

Go to Step 6

4

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

Does the Seat Lumbar Down parameter change state?

Go to Step 5

Go to Step 7

5

  1. Disconnect the lumbar vertical motor harness connector.
  2. Connect a test lamp between the lumbar motor up control circuit and the lumbar motor down control circuit of the harness connector.
  3. Operate the lumbar switch in the UP and DOWN directions.

Does 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 up switch signal circuit of the harness connector.
  3. With a scan tool, observe the Seat Lumbar Up parameter.

Does the Seat Lumbar Up 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 down switch signal circuit of the harness connector.
  3. With a scan tool, observe the Seat Lumbar Down parameter.

Does the Seat Lumbar Down parameter change state?

Go to Step 13

Go to Step 11

8

Test the lumbar motor up control circuit between the memory seat module and the lumbar vertical 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 down control circuit between the memory seat module and the lumbar vertical 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 up switch signal circuit between the lumbar switch and the memory seat module 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 down switch signal circuit between the lumbar switch and the memory seat module 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 memory seat module. 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 vertical motor. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 17

15

Replace the memory seat module. Refer to Memory Seat Control Module Replacement .

Did you complete the replacement?

Go to Step 18

--

16

Replace the lumbar switch. Refer to Lumbar Switch Replacement .

Did you complete the replacement?

Go to Step 18

--

17

Replace the lumbar vertical 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