Front Seat Lumbar Mechanism - Noises/Inoperative

Reference:
ITB99-031

Classification:
BT99-017

Date:
June 15, 1999

1997-99 Q45 FRONT SEAT LUMBAR SUPPORT MECHANISM INOPERATIVE

APPLIED VEHICLES: 1997-99 Q45

SERVICE INFORMATION

If the front seat lumbar support adjustment in a 1997-1999 Q45 does not function, or makes a grinding, popping or clicking sound when operating, use this bulletin to resolve the incident.

The lumbar support mechanism is now available as a replacement part. It is not necessary to replace the complete seat back.

SERVICE PROCEDURE

Diagnosis

1. Verify that the lumbar support mechanism is not working properly.

A. If the motor makes a whining noise and there is no movement or if there is a grinding, popping or clicking sound when operating, the lumbar mechanism should be replaced. Proceed to the Repair section.

B. If there is no sound when the lumbar support control switch is operated, proceed to step # 2.

2. Check for power to the lumbar support mechanism motor. Use diagnostic procedure 22 on Page EL-399 of the 1998 Q45 service manual to check the power supply, switch operation and harness continuity.

A. If these checks fail, this bulletin does not apply. Use the service manual to determine the cause of this incident.

B. If these checks are OK, the lumbar support mechanism should be replaced. Proceed to the Repair section.

Repair

Use the following procedure to replace the driver's side lumbar support mechanism. The passenger side process is identical with the exception of the lumbar mechanism part number. See the parts information table for appropriate part numbers.

Figure 1:

1. Remove the seat back cover. Move the seat full forward, and work from the rear. There are four retaining clips (two middle and two bottom) and two "L" shaped brackets (at the top) securing the cover to the seat back (see Figure 1). Start from the bottom and work upward, removing the retaining clips. Take care not to damage the seat back cover.

Figure 2:

2. Remove the nine leather attachment hooks (one on top, three on each side and two on the bottom) all the way around the backrest perimeter (see Figure 2).

3. Remove head rest and the head rest guides from the top of backrest.

Figure 3:

4. Move the seat all the way back and incline the seat back so the 2 attachment bolts are exposed (see Figure 3).

5. Use a 10 mm socket to loosen and remove the bolts On the driver's seat shown in Figure 3, they are on the right hand side of the seat back. (The bolts are on the left side of the backrest for the passenger seat.)

Figure 4:

6. Push the foam padding in the backrest forward and rotate the lumbar mechanism so it can be removed from the backrest (see Figure 4). Once outside the backrest, the wiring harness will be exposed and can be disconnected.


CAUTION: Do NOT unplug the SRS side air bag harness connectors. If these connectors are unplugged, use CONSULT to erase any trouble codes from the SRS control unit.

Figure 5:

7. Before installing the new lumbar mechanism, connect the wiring harness to the new mechanism (see Figure 5) and verify proper operation.

8. Install the mechanism in the backrest and attach with the two bolts.

9. Return the back rest foam to its original position.

10. Re-install the head rest guides and the head rest.

11. Re-secure the leather with the existing hooks.

12. Install the seatback cover.

13. Verify proper operation of the lumbar support mechanism.

PARTS INFORMATION





For Driver Side Lumbar Support Mechanism

CLAIMS INFORMATION





Submit a Primary Failed Part (PP) line using the claims coding as shown.