Restraints System (Service Information): CLOCKSPRING: Operation

The clockspring is a mechanical electrical circuit component that is used to provide continuous electrical continuity between the fixed instrument panel wire harness and certain electrical components mounted on or in the rotating steering wheel. On this vehicle the rotating electrical components include the Driver AirBag (DAB), the horn switch, the Electronic Vehicle Information Center (EVIC) switch pod, the speed control switch pod, the paddle shift switches and the remote radio switches. The clockspring is positioned and secured near the top of the steering column. The fixed connector receptacle on the back of the fixed Steering Column Control Module (SCCM) housing connects the clockspring to the vehicle electrical system through a take out with connector from the instrument panel wire harness.

The turn signal cancel cam is integral to the rim of the clockspring rotor hub within the SCCM housing so it also moves with the rotation of the steering wheel. Three short, sleeved pigtail wires on the upper surface of the clockspring rotor connect the clockspring to the DAB, while a steering wheel wire harness connected to the connector receptacle on the upper surface of the clockspring rotor completes circuits to the horn switch, the EVIC switch pod, the speed control switch pod, the paddle shift switches and the remote radio switches.

Like the clockspring in a timepiece, the clockspring tape has travel limits and can be damaged by being wound too tightly during full stop-to-stop steering wheel rotation. To prevent this from occurring, the clockspring is centered when it is installed on the steering column. Centering the clockspring indexes the clockspring tape to the movable steering components so that the tape can operate within its designed travel limits. However, if the steering shaft is disconnected from the steering gear the clockspring rotor spool can change position relative to other movable steering components. If clockspring centering has been compromised, the entire SCCM must be replaced with a new unit.

Service replacement clocksprings are shipped pre-centered and with a yellow plastic locking tab installed. This locking tab should not be removed until the clockspring has been properly installed on the steering column. The clockspring also includes an automatic spring-loaded blocker mechanism that will lock the clockspring rotor to the clockspring hub when the steering wheel is removed, and automatically unlock when the steering wheel has been properly installed.

The hardwired clockspring circuits may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the electronic controls and communication between stationary electronic modules and devices in the vehicle and the rotating electronic modules and devices on or in the steering wheel. The most reliable, efficient and accurate means to diagnose the electronic controls and communication related to clockspring operation requires the use of a diagnostic scan tool and may also require the use of the Airbag Kit. Refer to the appropriate diagnostic information.