Restraint System: CLOCKSPRING
| Refer to COMPONENT INDEX . |
The Steering Column Control Module (SCCM) is located near the top of the steering column below the steering wheel. The SCCM includes the clockspring, the left (lighting) multifunction switch, the right (wiper) multifunction switch, and a steering column power tilt and telescope switch (if equipped).
The SCCM is secured to the steering column by an integral band clamp on the bottom of the instrument panel side of the SCCM. The SCCM has a centering attachment screw located on the top of the instrument panel side of the SCCM to be certain the SCCM is centered properly on the steering column.
There are also unique lugs cast into the outer circumference of the steering wheel hub that must be engaged into slots within the inner circumference of the clockspring rotor hub to unlock and drive the clockspring. The steering wheel must be tightened to specification to ensure proper clockspring function.
The SCCM includes three integral connector receptacles that face toward the Driver AirBag (DAB) (front side) and are connected to the steering wheel electrical components through three take outs and connectors of the steering wheel wire harness. The 6-terminal receptacle at the 11 o'clock position contains the circuits for the DAB. The 12-terminal receptacle at the 1 o'clock position contains the circuits for a Local Interface Network (LIN) data bus to the Body Control Module (BCM) for the Electronic Vehicle Information Center (EVIC) switch data transmission, another LIN data bus for transmission of cruise control and Hands On Detection data, the horn signal, B(+) feed and ground for the LIN module (internal to the SCCM), steering wheel heater Negative Temperature Coefficient (NTC) feedback, and shifter paddle feedback (if equipped). The 2-terminal receptacle at the 5 o'clock position contains the heated steering wheel B(+) feed and return circuits to the Comfort Seat Wheel Module (CSWM) (if equipped). Both radio control switches are hardwired to the EVIC switch on the left steering wheel spoke, which then uses the LIN data bus to communicate with the BCM. The surface of the rotor hub facing the steering wheel (front side) also has a 6-terminal single connector for the Driver AirBag (DAB) with a Connector Position Assurance (CPA) lock. The pigtail connector contains the circuits for DAB function.
The SCCM also includes two integral connector receptacles that face toward the instrument panel (back side) and are connected to the vehicle electrical system through two take outs and connectors of the instrument panel wire harness. The 14-terminal receptacle at the 6 o'clock position contains the circuits for heated steering wheel (if equipped) from the CSWM and the Driver AirBag (DAB) from the Occupant Restraint Controller (ORC) module. The 16-terminal receptacle at the 9 o'clock position contains the circuits for the EVIC LIN data bus and the cruise and Hands On Detection LIN data bus to the BCM, the horn signal to the BCM, steering wheel heater Negative Temperature Coefficient (NTC) signal and return, shifter paddle signal and return (if equipped), fused B(+), ground and the Controller Area Network - Chassis (CAN-C) data bus.
Like the clockspring in a timepiece, the SCCM 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 SCCM is centered when it is installed on the steering column. Centering the SCCM indexes the SCCM tape to the movable steering components so that the tape can operate within its designed travel limits. If the steering wheel is removed from the steering column or if the SCCM is removed from the steering column, a spring-actuated automatic locking ring pops up from the face of the SCCM rotor to lock the rotor from rotation. However, if the locking ring is manually compressed or if the steering shaft is disconnected from the steering gear with the steering wheel installed, the SCCM spool can change position relative to the other steering components. Loss of SCCM centering will result in damage to the SCCM tape.
For additional information on the Operation of the SCCM. Refer to MODULE, STEERING COLUMN CONTROL (SCCM), DESCRIPTION AND OPERATION .
The service replacement SCCM is shipped with the clockspring 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 steering wheel is installed on a steering column, clockspring centering must be confirmed by viewing the inspection window on the clockspring rotor. If the black boxes of the clockspring tape are not visible in the inspection window, the entire SCCM must be replaced with a new unit. Refer to MODULE, STEERING COLUMN CONTROL (SCCM), REMOVAL AND INSTALLATION .
The clockspring cannot be repaired. If the clockspring is ineffective, damaged, or if the DAB has been deployed, the entire SCCM must be replaced. Refer to MODULE, STEERING COLUMN CONTROL (SCCM), REMOVAL AND INSTALLATION .