Restraints System (Service Information): 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 (DAB), the horn switch and, if the vehicle is so equipped, the odometer switch pod or the Electronic Vehicle Information Center (EVIC) switch pod, the Local Interface Network (LIN) module, the speed control switch pod 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) mounting 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 mounting 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 and, if the vehicle is so equipped, the odometer switch pod or the EVIC switch pod, the LIN module, the speed control switch pod 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. 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 clockspring 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. If the locking tab is removed before the clockspring 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 clockspring must be replaced with a new unit.

The hard wired 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 SRS Load Tool special tool along with the appropriate Load Tool Jumpers and Adapters. Refer to the appropriate diagnostic information.