GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1999 🢒 Eldorado 🢒 Body and Accessories 🢒 Seats 🢒 Lumbar Support Does Not Move Up or Down - Driver

Lumbar Support Does Not Move Up or Down - Driver AL2

Step

Action

Value(s)

Yes

No

DEFINITION: This table diagnoses the lumbar support, up down inoperative (option AL2) in the left seat.

1

Did you perform the Lumbar Support System Check?

--

Go to Step 2

Go to Lumbar Support System Check

2

Use a test lamp in order to backprobe the LH lumbar vertical relay connector from cavity C (RED) to ground.

Does the test lamp light?

--

Go to Step 3

Go to Step 11

3

Use a test lamp in order to backprobe the LH lumbar vertical relay connector from cavity C (RED) to cavity D (BLK).

Does the test lamp light?

--

Go to Step 4

Go to Step 12

4
  1. Place the LH lumbar switch in the UP position.
  2. Use a test lamp in order to backprobe the LH lumbar vertical relay connector from cavity A (RED) to ground.

Does the test lamp light?

--

Go to Step 5

Go to Step 13

5
  1. Place the LH lumbar switch in the DOWN position.
  2. Use a test lamp in order to backprobe the LH lumbar vertical relay connector from cavity F (YEL) to ground.

Does the test lamp light?

--

Go to Step 6

Go to Step 14

6
  1. Place the LH lumbar switch in the UP position.
  2. Use a test lamp in order to backprobe the LH lumbar vertical relay connector from cavity B (TAN) to ground.

Does the test lamp light?

--

Go to Step 7

Go to Step 16

7
  1. Place the LH lumbar switch in the DOWN position.
  2. Use a test lamp in order to backprobe the LH lumbar vertical relay connector from cavity E (PPL) to ground.

Did the test lamp light?

--

Go to Step 8

Go to Step 16

8

Test for an open or short to ground in CKT 768 (TAN or TAN/WHT) between the LH lumbar vertical relay and the LH lumbar vertical motor. Refer to Testing for Continuity or Testing for Short to Ground in Wiring Systems.

Is the wiring OK?

--

Go to Step 9

Go to Step 17

9

Test for an open or short to ground in CKT 767 (PPL or PPL/WHT) between the LH lumbar vertical relay and the LH lumbar vertical motor. Refer to Testing for Continuity or Testing for Short to Ground in Wiring Systems.

Is the wiring OK?

--

Go to Step 10

Go to Step 17

10

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

Is the lumbar vertical motor replacement complete?

--

Go to Lumbar Support System Check

--

11

Repair the open in CKT 742 (RED) between splice S352 and the LH lumbar vertical relay. Refer to Wiring Repairs in Wiring Systems.

Is the circuit repair complete?

--

Go to Lumbar Support System Check

--

12

Repair the open in CKT 850 (BLK) between splice S351 and the LH lumbar vertical relay. Refer to Wiring Repairs in Wiring Systems.

Is the circuit repair complete?

--

Go to Lumbar Support System Check

--

13

Test for an open or short to ground in CKT 387 (RED) between the LH lumbar switch and the LH lumbar vertical relay. Refer to Testing for Continuity or Testing for Short to Ground in Wiring Systems.

Is the wiring OK?

--

Go to Step 15

Go to Step 17

14

Test for an open or short to ground in CKT 386 (YEL) between the LH lumbar switch and the LH lumbar vertical relay. Refer to Testing for Continuity or Testing for Short to Ground in Wiring Systems.

Is the wiring OK?

--

Go to Step 15

Go to Step 17

15

Replace the LH lumbar switch. Refer to Lumbar/Heated Seat Switch Replacement - Power .

Is the lumbar switch replacement complete?

--

Go to Lumbar Support System Check

--

16

Replace the LH lumbar vertical relay.

Is the lumbar vertical relay replacement complete?

--

Go to Lumbar Support System Check

--

17

Repair the suspect wiring. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Lumbar Support System Check

--

Lumbar Support Does Not Move Up or Down - Driver A45

Step

Action

Value(s)

Yes

No

DEFINITION: This table diagnoses inoperative lumbar support (AL2) in the left seat equipped with memory function (A45). The diagnosis does not cover the left seat without the memory function (A45) or the right seat. For diagnoses of the lumbar support in the left seat without A45 or the right seat, refer to Lumbar Support System Check.

1

Did you perform the entire Lumbar Support: Memory System Check?

--

Go to Step 2

Go to Lumbar Support System Check

2
  1. Turn the ignition switch to the OFF position.
  2. Enter mode 1 diagnostics by grounding the memory seat module (MSM) diagnostic connector. The connector is located under the left seat. The connector must remain grounded during testing.
  3. One beep confirms entrance to mode 1 diagnostics.
  4. All seat motions will be disabled during mode 1 diagnostics.

Does the MSM beep once when entering mode 1 diagnostics?

--

Go to Step 3

Go to Step 7

3

Operate the LH lumbar switch in the inoperative position.

Does the MSM beep once when the switch was moved to the inoperative position?

--

Go to Step 11

Go to Step 4

4
  1. Disconnect the LH lumbar switch connector.
  2. Operate the LH seat lumbar switch in the inoperative position.
  3. Connect a J 39200 digital multimeter (DMM) between the LH lumbar switch connector cavity E (BLK) and the appropriate LH lumbar switch connector cavity:
    4. • Lumbar down: cavity C (YEL) (DeVille) or cavity D (YEL) (Eldorado)
    • Lumbar up: cavity D (RED) (DeVille) or cavity C (RED) (Eldorado)

Is the resistance less than the specified value?

5 ohms

Go to Step 5

Go to Step 6

5

Repair the open in the appropriate wiring:

    • Lumbar down: CKT 386 (YEL)
    • Lumbar up: CKT 387 (RED)

Refer to Wiring Repairs in Wiring Systems.

Is the circuit repair complete?

--

Go to Step 19

--

6

Replace the LH lumbar switch. Refer to Lumbar/Heated Seat Switch Replacement - Power .

Is the lumbar switch replacement complete?

--

Go to Step 19

--

7

Test for proper terminal contact at the MSM connectors. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

Is terminal contact OK?

--

Go to Step 19

--

8

Test for an open in CKT 1840 (ORN) between the MSM connector C2 cavity D and splice S306. Refer to Testing for Continuity in Wiring Systems.

Is the wiring OK?

--

Go to Step 9

Go to Step 15

9

Test for an open in CKT 850 (BLK) between the MSM connector C2 cavity C and splice S351. Refer to Testing for Continuity in Wiring Systems.

Is the wiring OK?

--

Go to Step 10

Go to Step 16

10

Test for an open in CKT 742 (RED) between the MSM connector C4 cavity B and splice S311. Refer to Testing for Continuity in Wiring Systems.

Is the wiring OK?

--

Go to Step 18

Go to Step 17

11
  1. Disconnect the suspect lumbar motor connector.
  2. Connect a fused jumper between battery positive voltage (B+) and one of the lumbar motor cavities.
  3. Connect a fused jumper between the other lumbar motor cavity and ground.

Does the motor run?

--

Go to Step 12

Go to Step 13

12

Repair the open or short to ground in the appropriate wiring:

    • Lumbar down: CKT 767 (PPL or PPL/WHT)
    • Lumbar up: CKT 768 (TAN or TAN/WHT)

Refer to Wiring Repairs in Wiring Systems.

Is the circuit repair complete?

--

Go to Step 19

--

13

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

Is the lumbar motor replacement complete?

--

Go to Step 19

--

14

Repair the appropriate terminals. Refer to Connector Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 19

--

15

Repair the open in CKT 1840 (ORN). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 19

--

16

Repair the open in CKT 850 (BLK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 19

--

17

Repair the open in CKT 742 (RED). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 19

--

18

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

Is the memory seat module replacement complete?

--

Go to Step 19

--

19

Perform the Lumbar Support System Check .

Is the system check complete?

--

System OK

--