Clockspring - Operation

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, the horn switch, the speed control switch, the remote radio switches, the hands-free communication switches and the Electronic Vehicle Information Center (EVIC) control switches, if the vehicle is so equipped.

The clockspring is integral to the Steering Column Control Module (SCCM) positioned and secured near the top of the steering column.Steering Column Module - Description. The turn signal cancel cam is integral to the rim of the clockspring rotor hub spool within the clockspring case so it also moves with the rotation of the steering wheel. Two short, sleeved pigtail wires on the upper surface of the clockspring rotor connect the clockspring to the Driver AirBag (DAB), while a steering wheel wire harness connected to the connector receptacles on the upper surface of the clockspring rotor completes circuits for the various steering wheel-mounted switches and the heated steering wheel, if the vehicle is so equipped.

Like the clockspring in a timepiece, the clockspring tape and conductors have 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. Clockspring centering must be confirmed by viewing the inspection window on the clockspring rotor. If the black squares of the clockspring tape are not visible in the inspection window, clockspring centering has been compromised and the entire SCCM must be replaced with a new unit. Steering Column Module - Installation.

Service replacement clocksprings are shipped pre-centered within the SCCM and with a plastic locking tab installed. This locking tab should not be removed until the SCCM has been properly installed on the steering column. If the locking tab is removed before the SCCM is installed on a steering column, clockspring centering must be confirmed by viewing the inspection window on the clockspring rotor. If the black squares of the clockspring tape are not visible in the inspection window, the SCCM must be replaced with a new unit. Proper clockspring installation may also be confirmed by viewing the Steering Angle Sensor (SAS) data using a diagnostic scan tool.

The hard wired clockspring circuits to the SCCM 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 SCCM, the Steering Control Module (SCM) or the electronic controls or communication between other modules and devices that provide some features of the Supplemental Restraint System (SRS). The most reliable, efficient, and accurate means to diagnose the electronic controls and communication related to SRS operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.