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 Power Seat 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 between the battery positive voltage circuit and 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 between the battery positive voltage circuit and 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 Front Seat Lumbar Control Switch Replacement or Rear Seat Lumbar Control Switch Replacement .

Did you complete the replacement?

Go to Step 18

--

17

Replace the lumbar vertical motor. Refer to Front Seat Lumbar Support Replacement or Rear 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

Lumbar Support Does Not Move Up or Down AM3 with A45

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests the integrity of the lumbar up switch. If the test lamp illuminates the switch is shorted in the active position. The switch parameter may not display active because, approximately 60 seconds after seeing the switch signal in the active state, the massage module shuts down and no longer relays the active switch signal to the memory seat module.

  2. This step tests the integrity of the lumbar down switch. If the test lamp illuminates the switch is shorted in the active position. The switch parameter may not display active because, approximately 60 seconds after seeing the switch signal in the active state, the massage module shuts down and no longer relays the active switch signal to the memory seat module.

  3. This step tests the integrity of the lumbar up signal circuit of the memory seat module. If the fuse in the jumper wire opens when you perform this test, the signal circuit is shorted to ground.

  4. This step tests the integrity of the lumbar down signal circuit of the memory seat module. If the fuse in the jumper wire opens when you perform this test, the signal circuit is shorted to ground.

  5. This step verifies that the massage module is receiving lumbar up motor control voltage from the memory seat module.

  6. This step verifies that the massage module is receiving lumbar down motor control voltage from the memory seat module.

  7. This step verifies the repair.

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 Seat 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

Operate the lumbar switch in the UP and DOWN directions.

Does the lumbar vertical motor run for approximately 1 second then stop?

Go to Step 24

Go to Step 4

4

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

Does the Seat Lumbar UP switch parameter change state?

Go to Step 5

Go to Step 6

5

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

Does the Seat Lumbar Down switch parameter change state?

Go to Step 12

Go to Step 8

6

  1. Disconnect the massage module harness connector.
  2. Connect a test lamp from the lumbar up switch signal circuit Pin-G of the massage module connector to a good ground.

Does the test lamp illuminate?

Go to Step 20

Go to Step 7

7

With the test lamp still connected from the lumbar up switch signal circuit Pin-G of the massage module connector to a good ground, operate the lumbar switch in the UP direction.

Does the test lamp illuminate?

Go to Step 10

Go to Step 15

8

  1. Disconnect the massage module harness connector.
  2. Connect a test lamp from the lumbar down switch signal circuit Pin-H of the massage module connector to a good ground.

Does the test lamp illuminate?

Go to Step 20

Go to Step 9

9

With the test lamp still connected from the lumbar down switch signal circuit Pin-H of the massage module connector to a good ground, operate the lumbar switch in the DOWN direction.

Does the test lamp illuminate?

Go to Step 11

Go to Step 15

10

  1. Connect a 3-amp fused jumper wire from battery positive voltage to the lumbar up signal circuit Pin-S of the massage module connector.
  2. With a scan tool, observe the Seat Lumbar Up switch parameter.

Does the Seat Lumbar Up switch parameter change state?

Go to Step 22

Go to Step 16

11

  1. Connect a 3-amp fused jumper wire from battery positive voltage to the lumbar down signal circuit Pin-R of the massage module connector.
  2. With a scan tool, observe the Seat Lumbar Down switch parameter.

Does the Seat Lumbar Down switch parameter change state?

Go to Step 22

Go to Step 16

12

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

Does the test lamp illuminate in both directions?

Go to Step 21

Go to Step 13

13

  1. Disconnect the massage module connector.
  2. Connect a test lamp from the lumbar motor up control circuit Pin-E of the massage module connector to a good ground.
  3. With a scan tool, command the Lumbar Up.

Does the test lamp illuminate?

Go to Step 14

Go to Step 17

14

  1. Connect a test lamp from the lumbar motor down control circuit Pin-F of the massage module connector to a good ground.
  2. With a scan tool, command the Lumbar Down.

Does the test lamp illuminate?

Go to Step 18

Go to Step 17

15

Test the lumbar up/down switch signal circuits between the lumbar switch and the massage module for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 29

Go to Step 20

16

Test the lumbar up/down signal circuits between the massage module and the memory seat module for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 29

Go to Step 23

17

Test the lumbar motor up/down control circuits between the memory seat module and the massage module for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 29

Go to Step 23

18

Test the lumbar motor up/down control circuits between the massage module and the lumbar vertical motor for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 29

Go to Step 19

19

Test the lumbar vertical position sensor signal circuit between the sensor and the massage module for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 29

Go to Step 22

20

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 29

Go to Step 25

21

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 29

Go to Step 26

22

Inspect for poor connections at the harness connector of the massage module. Refer to Circuit Testing and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 29

Go to Step 27

23

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 29

Go to Step 28

24

Repair the open in the low reference circuit of the lumbar vertical position sensor. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

--

25

Replace the lumbar switch. Refer to Front Seat Lumbar Control Switch Replacement .

Did you complete the replacement?

Go to Step 29

--

26

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

Did you complete the replacement?

Go to Step 29

--

27

Replace the massage module. Refer to Massaging Lumbar Control Module Replacement .

Did you complete the replacement?

Go to Step 29

--

28

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

Did you complete the replacement?

Go to Step 29

--

29

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 AM3 w/o A45

Step

Action

Value (s)

Yes

No

Schematic Reference: Lumbar Support Schematics

Connector End View Reference: Power Seat Connector End Views

1

Did you review the lumbar vertical 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 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

Measure the voltage from the battery positive voltage circuit of the massage module harness connector to a good ground.

Does the voltage measure within the specified range?

9-16 V

Go to Step 4

Go to Step 20

4

Measure the voltage from the battery positive voltage circuit of the massage module harness connector to the ground circuit of the massage module.

Does the voltage measure within the specified range?

9-16 V

Go to Step 5

Go to Step 21

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 18

Go to Step 6

6

  1. Connect a test lamp from the lumbar motor up signal circuit of the massage module connector to a good ground.
  2. Operate the lumbar UP switch.

Does the test lamp illuminate?

--

Go to Step 7

Go to Step 15

7

  1. Connect a test lamp from the lumbar motor down signal circuit of the massage module connector to a good ground.
  2. Operate the lumbar DOWN switch.

Does the test lamp illuminate?

--

Go to Step 8

Go to Step 16

8

  1. Disconnect the harness connector of the lumbar vertical position sensor.
  2. Operate the lumbar switch in the UP or DOWN direction in order to wake up the massage module.
  3. Measure the voltage from the 5 volt reference circuit of the harness connector to a good ground.

Does the voltage measure within the specified range?

4.50-5.50 V

Go to Step  9

Go to Step  13

9

  1. Operate the lumbar switch in the UP or DOWN direction in order to wake up the massage module.
  2. Measure the voltage from the signal circuit of the lumbar vertical position sensor harness connector to a good ground.

Does the voltage measure within the specified range?

4.50-5.50 V

Go to Step  10

Go to Step  11

10

Test the lumbar motor control circuits between the massage module and the lumbar vertical motor for a short to ground, high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step  25

Go to Step  18

11

Test the signal circuit of the lumbar vertical position sensor 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  25

Go to Step  12

12

Test the signal circuit of the lumbar vertical position sensor for a short to battery voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step  25

Go to Step  19

13

Test the 5 volt reference circuit of the lumbar vertical position sensor 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  25

Go to Step  14

14

Test the 5 volt reference circuit of the lumbar vertical position sensor for a short to battery voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step  25

Go to Step  19

15

Test the lumbar motor up signal circuit between the lumbar switch and the massage module 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  25

Go to Step  17

16

Test the lumbar motor down signal circuit between the lumbar switch and the massage module 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  25

Go to Step  17

17

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  25

Go to Step  22

18

Inspect for poor connections at the harness connectors of the lumbar vertical motor/position sensor assembly. 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  25

Go to Step  23

19

Inspect for poor connections at the harness connector of the lumbar massage 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  25

Go to Step  24

20

Repair the open in the battery positive voltage circuit of the lumbar massage module. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step  25

--

21

Repair the open in the ground circuit of the lumbar massage module. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step  25

--

22

Replace the lumbar switch. Refer to Front Seat Lumbar Control Switch Replacement .

Did you complete the replacement?

--

Go to Step  25

--

23

Replace the lumbar vertical motor/position sensor assembly. Refer to Front Seat Lumbar Support Replacement .

Did you complete the replacement?

--

Go to Step  25

--

24

Replace the lumbar massage module. Refer to Massaging Lumbar Control Module Replacement .

Did you complete the replacement?

--

Go to Step  25

--

25

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step  2