GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Lumbar Support Schematics

Important: This table assumes that the mechanical systems are clear and free of obstructions.

1

Did you review the Lumbar Support Description and Operation?

Go to Step 2

Go to Symptoms - Seats

2

Operate the Lumbar/Bolster system.

Does the system operate normally?

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

Go to Step 3

3

Are both the lumbar and the bolster motors inoperative?

Go to Step 4

Go to Step 6

4

  1. Disconnect the lumbar/bolster switch connector.
  2. Connect a test lamp from the battery voltage supply circuit terminal in the harness connector to a good ground.

Does the test lamp illuminate?

Go to Step 5

Go to Step 10

5

Connect a test lamp from the battery voltage supply circuit terminal to the ground circuit terminal in the lumbar/bolster switch harness connector.

Does the test lamp illuminate?

Go to Step 8

Go to Step 11

6

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

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

Go to Step 9

Go to Step 7

7

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

Did you find and correct the condition?

Go to Step 14

Go to Step 8

8

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

Did you find and correct the condition?

Go to Step 14

Go to Step 13

9

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

Did you find and correct the condition?

Go to Step 14

Go to Step 12

10

Repair the open or short to ground in the battery voltage supply circuit to the lumbar/bolster switch. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 14

--

11

Repair the open in the lumbar/bolster switch ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 14

--

12

Replace the inoperative motor. Refer to Front Seat Lumbar Support Replacement .

Did you complete the replacement?

Go to Step 14

--

13

Replace the inoperative lumbar/bolster switch. Refer to Lumbar Switch Replacement .

Did you complete the replacement?

Go to Step 14

--

14

Operate the system to verify the repair.

Did you correct the condition?

System OK

Go to Step 2