Correction For Seat Assembly Movement

Correction for Seat Assembly Movement or Chucks/Rocks (1997-2000 Park Avenue, Park Avenue Ultra Models)

A design change to the horizontal actuator assembly has been made. Service parts have been released and are now available. Replace the driver and/or passenger seat adjuster horizontal actuator assembly with the following procedure.

However, in diagnosing the above listed vehicles, it is important not to overlook other obvious repairs prior to replacing the horizontal actuator assembly on the seat adjuster frame.

Diagnosis

1. Verify that both rear seat-to-floorpan attaching bolts are not loose. If one or both of the bolts are loose, loosen both bolts, and with someone sitting in the seat, tighten the outer bolt first then the inner bolt in order to secure the seat to the floorpan.

Tighten

Tighten the bolts to 35 N.m (26 lb ft).
2. Verify that the front adjuster attachment hooks are properly engaged to the floorpan. Check the seat for a rocking condition. If the condition is corrected, no further repair is necessary. If the condition persists, proceed to the removal procedure.

Removal Procedure

1. Prior to removing the seat assembly:

^ Position the vertical travel fully up.

^ Position the headrest fully down.

^ Position the recliner within approximately five degrees of fully forward.

^ Position the inner seat adjuster rail even with the outer seat adjuster rail.

2. Remove the seat assembly.

Refer to the Seat sub-section of the Service Manual.

3. On vehicles equipped with memory seats:

^ Place the driver's seat assembly right side up on a clean protected surface.

^ Remove the two front screws from the memory seat module bracket using a 90 degree screwdriver.

4. Place the seat assembly upside down with the seat back to the front on a clean protected surface.

5. Disconnect the electrical connector from the horizontal drive actuator.

This connector consists of a green wire and a beige wire.

Note which wire corresponds to which connector pin in the actuator.

6. On vehicles equipped with memory seats, disconnect the electrical connector from the horizontal drive actuator.





7. Remove the horizontal nut cage bolts (4) from the horizontal drive actuator assembly (7). There are 4 per assembly, (the outer rails (3) will slide back.)

8. Remove the horizontal drive bolts (2) from the horizontal drive actuator assembly (7). There are 4 per assembly.

9. Separate the inner rails (1) and the horizontal drive actuator assembly (7) slightly in order to disengage the horizontal drive actuator assembly from the seat adjuster frame assembly.

10. Remove the horizontal drive assembly (7) by pulling forward.

11. Remove the two nylon bushings (8) from the "L" bracket on the inner rail.

Installation Procedure

1. Lightly lubricate two new nylon bushings with grease.

2. Install the two new nylon bushings (8) into the "U" bracket on the inner rail.

The large flange must be on the side facing the horizontal drive actuator.

3. Ensure that both horizontal nut cages (5) are threaded all the way down the lead screws to the horizontal drive housing. Install the horizontal drive actuator assembly.

4. On vehicles equipped with memory seats, ensure the memory module bracket slides into the slots of the horizontal drive actuator assembly.

5. Insert the horizontal lead screw ends into the nylon bushings.

6. Install the two horizontal drive nuts (6) into the two recesses located on the inboard side of the horizontal drive housing. Install the horizontal drive bolts (2). There are 4 per assembly.

Tighten

Tighten the bolts to 18 N.m (13 lb ft).

7. Slide the outer rails (3) over the inner rails (1). Align the horizontal nut cages (5) with the nut brackets on the outer rails.

8. install the horizontal nut cage bolts (4). There are 4 per assembly.

Tighten

Tighten the bolts to 18 N.m (13 lb ft).

9. On vehicles equipped with memory seats, connect the electrical connector to the horizontal drive actuator.

10. Lubricate the lead screw with grease.

11. Power the seat adjuster assembly to the full forward position by using fused jumpers to apply battery positive voltage at the beige wire pin of the horizontal drive actuator connector body and battery ground to the green wire pin. Make sure the adjuster bottoms on the housing.

12. Power the seat adjuster assembly back to the full rearward position by reversing the fused jumper connections made in Step 11. Ensure the front end of the inner rails are even with the front end of the outer rails. This position is approximately 20 mm (3/4 inch) forward of full rear seat travel.

13. Connect the electrical connector to the horizontal drive actuator.

14. Place the seat in an upright position. Install the two front screws to the memory seat module bracket.

15. Install the seat into the vehicle. Refer to the Seat Replacement section of the Service Manual.

^ Ensure that the front adjuster attachment hooks are properly engaged to the floorpan.

^ Install the outboard rail first to avoid unparalleled rails.

^ Ensure the inboard rail bolt has a washer present.

16. Check the power seat adjuster for proper operation.

Parts Information





Parts are currently available from GMSPO.

Warranty Information





For vehicles repaired under warranty, use the table.