Clockspring Assembly / Spiral Cable: Description and Operation
WARNING: To service any component of the SCCM, the entire assembly must be removed from the column. This must be done due to the clockspring passing through the assembly and into the self docking connector. Failure to remove the assembly could damage the pins of the clockspring and prevent the airbag system from operating properly.
The clockspring assembly is secured with three screws (1) onto the top of the Steering Column Control Module (SCCM) near the top of the steering column behind the steering wheel.
The clockspring consists of a flat, round molded plastic case. Within the plastic case is a spool-like molded plastic rotor with a hub. The surface of the rotor hub has a large center hole. Within the plastic case and wound around the rotor spool is a long ribbon-like tape that consists of several thin copper wire leads sandwiched between two thin plastic membranes. The outer end of the tape terminates at the connector terminals that align themselves into the SCCM self-docking connector that faces the instrument panel, while the inner end of the tape terminates at the pigtail wires and connector receptacles on the hub of the clockspring rotor that face the steering wheel.
Service replacement clocksprings are shipped precentered and with the screws backed out and holding the clockspring into place. If reusing a clockspring or installing a new one that you are unsure if it is centered or not.
The clockspring cannot be repaired. If the clockspring is faulty, damaged, or if the driver airbag has been deployed, the clockspring must be replaced.
The clockspring is a mechanical electrical circuit component that is used to provide continuous electrical continuity between the fixed instrument panel wire harness and the electrical components mounted on or in the rotating steering wheel. On this model the rotating electrical components include the:
- Driver Airbag
- Horn Switch
- Steering Wheel Switches (if the vehicle is so equipped)
The clockspring case is positioned and secured to Steering Column Control Module (SCCM) mounting housing near the top of the steering column. The connector terminals on the tail of the fixed clockspring case connect the clockspring to the vehicle electrical system through the self-docking connector in the instrument panel wire harness.
The clockspring rotor is movable and is keyed to the steering column shaft that is molded onto the rotor hub. The lobe on the turn signal cancel cam on the lower surface of the clockspring rotor hub contact a turn signal cancel actuator of the multi-function switch to provide automatic turn signal cancellation.
Two short, yellow-sleeved pigtail wires on the upper surface of the clockspring rotor connect the clockspring to the multistage driver airbag, while a steering wheel wire harness connects the two connector receptacles on the upper surface of the clockspring rotor to the horn switch feed pigtail wire connector and, if the vehicle is so equipped, to the optional steering wheel switches on the steering wheel.
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 clockspring is removed from the steering column or if the steering shaft is disconnected from the steering gear, the clockspring spool can change position relative to the movable steering components. The clockspring must be re-centered following completion of this service or the tape may be damaged.
Service replacement clocksprings are shipped pre-centered. The screws that retain the clockspring to the SCCM should not be removed until the clockspring has been installed on the SCCM. If the screws have been removed before the clockspring is installed on the SCCM, the clockspring centering procedure must be performed.
The clockspring is located within the SCCM. If the clockspring has to be replaced. Service and Repair