GM Service Manual Online
For 1990-2009 cars only

Lumbar Support Inoperative w/o Memory

Step

Action

Yes

No

Schematic Reference: Driver Seat Schematics and Passenger Seat Schematics

Connector End View Reference: Power Seat Connector End Views

1

Did you review the Lumbar System Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Power Seats

2

Verify the condition is present.

Does the system operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Disconnect the inoperative lumbar or torso motor connector.
  2. Connect a test lamp between the motor control circuit terminals in the harness connector.
  3. Operate the appropriate switch in both directions.

Does the test lamp illuminate when the switch is operated in both directions?

Go to Step 6

Go to Step 4

4

Test the motor control circuits for an open or short to ground. Refer to Circuit Testing and to Wiring Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 5

5

Inspect for poor connections at the lumbar switch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 7

6

Inspect for poor connections at the inoperative lumbar or torso motor. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 8

7

Replace the lumbar switch. Refer to Lumbar Switch Replacement .

Go to Step 9

--

8

Replace the lumbar support/torso bolster motor assembly. Refer to Front Seat Lumbar Support Replacement .

Is the repair complete?

Go to Step 9

--

9

Operate the system to verify the repair.

Did you correct the condition?

System OK

Go to Step 3

Lumbar Support Inoperative with Memory

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

2

Verify the condition is present.

Does the system operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Install a scan tool.
  2. Observe the Lumbar and Torso Switch parameters in the driver seat module (DSM) Input/Output data list.

Do any of the Lumbar or Torso Switch parameters display Active?

Go to Step 4

Go to Step 5

4

Disconnect the lumbar adjuster switch connector.

Do all of the Lumbar or Torso Switch parameters display Inactive?

Go to Step 18

Go to Step 13

5

  1. Observe the Lumbar Forward Switch parameter in the DSM Input/Output data list.
  2. Operate the lumbar forward switch.

Does the scan tool display the lumbar forward switch as active?

Go to Step 6

Go to Step 9

6

  1. Observe the Lumbar Rearward Switch parameter in the DSM Input/Output data list.
  2. Operate the lumbar rearward switch.

Does the scan tool display the lumbar rearward switch as active?

Go to Step 7

Go to Step 10

7

  1. Observe the Torso Inward Switch parameter in the DSM Input/Output data list.
  2. Operate the torso inward switch.

Does the scan tool display the torso inward switch as active?

Go to Step 8

Go to Step 11

8

  1. Observe the Torso Outward Switch parameter in the DSM Input/Output data list.
  2. Operate the torso outward switch.

Does the scan tool display the torso outward switch as active?

Go to Step 19

Go to Step 12

9

  1. Disconnect the lumbar switch connector.
  2. Connect a fused jumper wire from the battery voltage supply circuit terminal to the lumbar forward switch signal circuit terminal in the harness connector.

Does the scan tool display the lumbar forward switch as Active?

Go to Step 18

Go to Step 14

10

  1. Disconnect the lumbar switch connector.
  2. Connect a fused jumper wire from the battery voltage supply circuit terminal to the lumbar rearward switch signal circuit terminal in the harness connector.

Does the scan tool display the lumbar rearward switch as Active?

Go to Step 18

Go to Step 15

11

  1. Disconnect the lumbar switch connector.
  2. Connect a fused jumper wire from the battery voltage supply circuit terminal to the torso inward switch signal circuit terminal in the harness connector.

Does the scan tool display the torso inward switch as Active?

Go to Step 18

Go to Step 16

12

  1. Disconnect the lumbar switch connector.
  2. Connect a fused jumper wire from the battery voltage supply circuit terminal to the torso outward switch signal circuit terminal in the harness connector.

Does the scan tool display the torso outward switch as Active?

Go to Step 18

Go to Step 17

13

Test the active lumbar or torso switch signal circuit for a short to voltage. Refer to Circuit Testing and to Wiring Repairs .

Did you find and correct the condition?

Go to Step 22

Go to Step 19

14

Test the lumbar forward switch signal circuit for an open or high resistance. Refer to Circuit Testing and to Wiring Repairs .

Did you find and correct the condition?

Go to Step 22

Go to Step 19

15

Test the lumbar rearward switch signal circuit for an open or high resistance. Refer to Circuit Testing and to Wiring Repairs .

Did you find and correct the condition?

Go to Step 22

Go to Step 19

16

Test the torso inward switch signal circuit for an open or high resistance. Refer to Circuit Testing and to Wiring Repairs .

Did you find and correct the condition?

Go to Step 22

Go to Step 19

17

Test the torso outward switch signal circuit for an open or high resistance. Refer to Circuit Testing and to Wiring Repairs .

Did you find and correct the condition?

Go to Step 22

Go to Step 19

18

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

Did you find and correct the condition?

Go to Step 22

Go to Step 20

19

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

Did you find and correct the condition?

Go to Step 22

Go to Step 21

20

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

Did you complete the replacement?

Go to Step 22

--

21

Replace the DSM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 22

--

22

Operate the system to verify the repair.

Did you correct the condition?

System OK

Go to Step 3