Theory Of Operation
The left and right paddle shift switches are normally open, resistor multiplexed momentary switches that are hard wired to the Steering Column Control Module (SCCM). The SCCM provides a five volt signal and return circuit to the paddle shift switches. The left and right paddle shift switches share the signal and return circuits. The SCCM detects the status of the paddle shift switches by reading the voltage drop of the signal circuit.
When the SCCM detects an input (voltage drop) from any one of the paddle shift switches, the SCCM broadcasts the switch status message over the CAN Bus to the Transmission Control Module (TCM), communicating the driver's request for transmission upshift or downshift.