Title:

Clockspring-Airbag Upgrade

Number:

PB_668

Release Date:

01/23/24

Revision Number:

Not Applicable

Revision Date:

Not Applicable

Chassis Type:

Custom Chassis

Component Description:

Clockspring-Airbag

Parts:

See Parts Table Below

Tools:

Steering wheel puller, torque wrench (lb-in and lb-ft), terminal remover tool, rotary tool,
torque seal

Purpose:
IMPORTANT: This procedure should not be performed by any personnel who have not taken Pierce Side
Roll Protection (SRP)/Frontal Protection training.
The steering column clockspring airbag (Pierce PN 1799451) has become obsolete and will require replacement if
it becomes damaged. The upgrade to the new clockspring-airbag will require a new clockspring and/or driver side
airbag.
Identify what parts are on your vehicle and what needs to be replaced.
If you have a Driver Steering Wheel Airbag, and do not have the newer version of the airbag, then you will need to
purchase both the new clockspring and new airbag:
• Steering Wheel Airbag (Pierce PN 1845916 or older); needs replacement
• Clockspring (Pierce PN 1799451); needs replacement
If you have the current airbag or newer, then you will only need to purchase a new part of whichever is being
replaced (airbag or clockspring):
• Steering Wheel Airbag (Pierce PN: 4081844, 4379803, or newer [DIACEL]), or
• Clockspring, Steering Column (Pierce PN 4312071)
If you have steering wheel controls without a Driver Airbag, you will only need to replace the clock spring and the
upper airbag:
• Clockspring, Steering Column (Pierce PN 4312071)
Procedure:
The following parts may need to be purchased in order to perform this procedure, depending on what needs to be
replaced:
Part

Description

Qty

4379803

AIR BAG,DRIVER,STEERING WHEEL

1

4312071
64-1218-0020
64-2408-0020

CLOCKSPRING,STEERING COLUMN
CONNECTOR BODY,4 MALE MTRI-P
LOCK,SECONDARY,4 METRI-PACK

1
1
1

Pa g e

1

o f

1 9

PARTS BULLETIN #668

Shown below is a reference for the clockspring-airbag connector style on the new clockspring versus the old
clockspring:

NOTE: Depending on configuration of your system, some steps may not be required to replace the airbag
and/or clockspring.
1. Turn steering wheel until steering wheel is centered and wheels are facing straight forward.
2. Identify if an airbag is on your vehicle.

•

Ensure power is turned OFF prior to performing.

3. Turn ignition switch and battery switch to OFF position.
4. Disconnect batteries.

Pa g e

2

o f

1 9

PARTS BULLETIN #668

5. Disconnect clockspring wire harness connector from yellow connector at the base of the steering column.
6. Refer to the SRS warning tag for further details.
NOTE: Note routing of wires prior to removal to ensure proper installation.

7. Position steering wheel telescopic adjustment to highest position in order to gain access to steering wheel
fasteners.
8. Loosen two Allen head fasteners. Fasteners are recessed approximately 1.5 in (38 mm) and access is
gained from the back side of the steering wheel through two access holes.
9. Loosen airbag assembly from steering wheel.
Pa g e

3

o f

1 9

PARTS BULLETIN #668

10. Lift airbag assembly vertically on steering wheel near mounting area, disconnect wires from airbag
inflator, horn, and steering wheel controls.
a. Yellow = Airbag
b. Brown = Horn
c. Black = Steering Wheel Controls
11. Place the airbag in a safe location with the plastic side facing upwards.
12. Safely dispose of airbag according to SRP training.

Pa g e

4

o f

1 9

PARTS BULLETIN #668

13. Remove steering wheel nut from steering wheel and steering column shaft.

Pa g e

5

o f

1 9

PARTS BULLETIN #668

14. Matchmark and note position of steering wheel on steering column.
NOTE: Ensure clockspring connectors are removed from steering wheel passthrough.
15. Install steering wheel puller on steering wheel and steering column and remove steering wheel from
steering column.

Pa g e

6

o f

1 9

PARTS BULLETIN #668

16. Remove steering wheel gap hider from steering column.

17. Remove upper and lower steering column covers from steering column.
Pa g e

7

o f

1 9

PARTS BULLETIN #668

NOTE:
• Note routing of wires prior to removal to ensure proper installation.
• Note position of cable ties prior to removal to ensure proper installation.
18. Remove two cable ties and clockspring wire harness from steering column.

19. Remove screw, cable tie, and wire harness from steering column.
Pa g e

8

o f

1 9

PARTS BULLETIN #668

NOTE: Note routing of wire harness.
20. Remove wire harness from steering column cover.

21. Remove two screws and clockspring from locating plate.
Pa g e

9

o f

1 9

PARTS BULLETIN #668

NOTE:
• The driver airbag connector on the new clockspring is slightly larger than the old connector. The
steering wheel wire passthrough may need some of the rubber removed to allow enough room for
the now larger connector.
• Only remove as much rubber from steering wheel passthrough as is needed to pass clockspring
wire harness through.
22. Using rotary tool, remove rubber from steering wheel passthrough.

NOTE:
• The yellow connector on the new clockspring is slightly larger than the old connector. The yellow
connector will need to be de-pinned and removed from the two wires in order to pass the wires
through the locating plate and steering column cover, then re-pinned.
• Note position of connector terminals prior to removal.
23. Using terminal remover tool, press in two side tabs and remove connector lock from yellow connector on
new clockspring (Pierce PN 4312071).

Pa g e

1 0

of

19

PARTS BULLETIN #668

24. Using terminal remover tool, release two terminal latches and remove terminals from connector.

25. Extend terminal latches if they were compressed during removal.

Pa g e

1 1

of

19

PARTS BULLETIN #668

26. Route new clockspring wire harness through locating plate and install clockspring on locating plate with
two screws. Tighten to 4.4-8.9 lb-in (0.5-1 N⋅m).

27. Route new clockspring wire harness through steering column cover as noted prior to removal.

Pa g e

1 2

of

19

PARTS BULLETIN #668

NOTE:
• Ensure there is enough slack available above the cushion clip so that steering column can
telescope fully without pulling on the clockspring wire harness and connectors. The yellow tape
on wire harness is an indicator for a proper securement point.
• One cable tie should be secure in the shown position at the yellow tape and the other should be
secured at the tilt shaft.
28. Secure wire harness on steering column with two cable ties.

29. Secure wire harness on steering column with cushion clip and screw.
Pa g e

1 3

of

19

PARTS BULLETIN #668
NOTE: When re-pinning connector, ensure terminal latches are extended so they lock securely into
connector.
30. Re-pin yellow connector on new clockspring wire harness.
31. Perform a tug test to ensure terminal latches are secure within connector.

32. Install upper and lower steering column covers on steering column.
33. Remove shipping clip from clockspring.

NOTE: Ensure connector is positioned properly in open slot of gap hider. Some material may need to be
removed from gap hider in order to properly position connector.
34. Install steering wheel gap hider on steering column.
Pa g e

1 4

of

19

PARTS BULLETIN #668

NOTE: Ensure matchmarks on steering wheel and steering column shaft are lined up properly.
35. Route wire harness through steering wheel passthrough and position steering wheel on steering column.

36. Install steering wheel on steering column shaft with steering wheel nut. Tighten to 60 lb-ft (81.3 N⋅m).
37. Apply torque seal to steering wheel nut and steering column shaft.
Pa g e

1 5

of

19

PARTS BULLETIN #668

NOTE:
• Airbag shown without wires connected for clarity.
• For steering wheels with no controls, the horn connector can be slid away from the airbag
connector as needed for clearance.
• Ensure the airbag connector does not contact the horn button connector.
• Ensure connectors are secured properly.
38. Connect wires to airbag inflator, horn, and steering wheel controls.
a. Yellow = Airbag
b. Brown = Horn
c. Black = Steering Wheel Controls

Pa g e

1 6

of

19

PARTS BULLETIN #668

NOTE:
• The U-plate is the “U” shaped, flat metal plate on the steering wheel chassis.
• Ensure wires are routed within 1.0” of edge of U-plate.
• Ensure wires are connected to flow naturally in a direction toward the U-plate. This will ensure
wires are not pinched during the horn button operation. Spinning the connector 180º can help the
wires to flow in the correct direction.
39. Route wires within steering wheel as shown.

Pa g e

1 7

of

19

PARTS BULLETIN #668

40. Secure airbag wire and steering wheel controls wire to lower U-plate with cable tie.

41. Place airbag assembly onto steering wheel and nest onto receiver U-plate.
42. The clinch nuts in the airbag assembly are torque prevailing to ensure that fasteners do not vibrate loose
during the life of the system. Resistance will be felt once the first threads become engaged. Tighten to 96
lb-in (10.8 N·m).
43. Check that the assembly rests flush with the steering wheel spokes and that it is firmly secured in place.
Downward travel of up to 1/8” (3mm) to activate the horn is normal.

Pa g e

1 8

of

19

PARTS BULLETIN #668

NOTE: The 2-pin connector installed on the cab SRS harness at the bottom of the steering column will
need to be replaced with a 4-pin connector.
44.
45.
46.
47.
48.
49.
50.
51.

Using terminal remover tool, remove blue secondary lock from old connector to unpin terminals.
Using terminal remover tool, remove terminal pin (CKT R033) from terminal A of original connector.
Install terminal pin (CKT R033) into position A1 of 4-pin connector (Pierce PN 64-1218-0020).
Using terminal remover tool, remove terminal pin (CKT R034) from terminal B of original connector.
Install terminal pin (CKT R034) into position A2 of 4-pin connector.
Perform a tug test.
Install new secondary lock (Pierce PN 64-2408-0020) between the wires in 4-piece connector.
Connect clockspring wire harness connector to yellow connector at the base of the steering column and
stow/secure wire harness as needed.
52. Test steering wheel tilt, telescoping, and rotation.

IMPORTANT: The following steps MUST be performed prior to activating the battery switch.
53.
54.
55.
56.

Turn the ignition key to ON position.
Exit vehicle.
After checking that no one is inside the vehicle, turn the battery disconnect switch to the ON position.
Verify that there are no SRS codes present.

If any additional support is needed, please open a technical support incident on Pierceparts.com.

Pa g e

1 9

of

19