Steering Column Control Module
STEERING COLUMN CONTROL MODULEDESCRIPTION
This vehicle is equipped with a Steering Column Control Module (SCCM) that houses a clockspring (2), the left multi-function switch (1), and the right multi-function switch (3). The SCCM is secured near the top of the steering column below the steering wheel and is completely concealed beneath the steering column shrouds. The SCCM is installed as a modular unit that supports the left (lighting) multi-function switch (1) and the right (wiper) multi-function switch (3). The controls for each of these switches extend through appropriate clearance holes provided in the steering column shrouds.
The SCCM utilizes integrated circuitry and information carried on the Controller Area Network (CAN) data bus along with several hard wired analog and multiplexed inputs to monitor both the right and left multifunction switches, the ignition switch, the horn switch, and the speed control switches. In response to those inputs, the SCCM controls and integrate many electronic functions and features of the vehicle through both hard wired outputs and the transmission of electronic message outputs to other electronic modules in the vehicle over the CAN data bus.
The clockspring is contained within a flat, round molded plastic case (1). The back (instrument panel side) of the case has an integral mounting bracket that is secured to the stationary steering column housing with three screws.
The electronics for the lighting functions and the wiper functions are located in the left lighting stalk, or left multi-function switch. There is a jumper wire from the wiper stalk that connects to the lighting stalk. The messages are than sent over the LIN bus to the Cab Compartment Node (CCN) and the CCN then transfers the message to the TIPM on the CAN bus.
A service replacement SCCM is shipped with the clockspring pre-centered and with a molded plastic locking pin installed. The locking pin secures the centered clockspring rotor to the SCCM case during shipment and handling, but must be removed after the SCCM is installed on the steering column and the steering wheel is installed.
If faulty or damaged, each component of the SCCM can be replaced individually, including the clockspring, and the left and right multi-function switches.
OPERATION
The Steering Column Control Module (SCCM) contains the clockspring, the left (lighting) multi-function switch, and the right (wiper/washer multi-function switch. The SCCM communicates over the Controller Area Network (CAN) data bus with other electronic modules in the vehicle and/or a diagnostic scan tool. The horn switch circuits pass through the clockspring to the Cab Compartment Node (CCN) and the CCN sends a CAN message to the Totally Integrated Power Module (TIPM) to control the horn. The CCN stores Diagnostic Trouble Codes (DTCs) for the SCCM. The right (wiper) multi-function switch has several inputs to the CCN.
The SCCM is connected to a fused B(+) circuit and receives a path to ground at all times. These connections allow it to remain functional regardless of the ignition switch position. The driver airbag squib circuits of the clockspring, the horn, and the speed control switch circuits pass through the SCCM, but the SCCM does not monitor, and has no control outputs related to these circuits. Any other input to the SCCM that would cause a vehicle system to function but does not require that the ignition switch be in the On position, such as turning on the lights or sounding the horn, prompts the SCCM to wake up and transmit on the CAN data bus.