Switch, MULTIFUNCTION: Description
The left multi-function switch is located on the left side of the steering column, just below the steering wheel. This switch is the primary control for the turn signals and for the headlamp beam selection. The only visible components of the switch are the control stalk (2) and the control knob (1) that extend through the steering column shrouds on the left side of the column. The remainder of the switch including its mounting provisions, its electrical connections and the turn signal cancel actuator are concealed within the Steering Column Control Module (SCCM) mounting housing beneath the shrouds.
The multi-function switch controls as well as the SCCM mounting housing are constructed of molded black plastic. Each of the switch controls has white International Control and Display Symbol graphics applied to it, which clearly identify its many functions. The multi-function switch is integral to the SCCM mounting housing.
The SCCM mounting housing is located near the top of the steering column below the steering wheel. In addition to the integral multi-function switch the SCCM mounting housing incorporates the Steering Control Module (SCM) and has integral features to support the mounting of the clockspring. All of the multi-function switch inputs and outputs are directly connected to the SCM. The SCM is an electronic microcontroller that serves as a Local Interface Network (LIN) master node and also as a gateway to the Controller Area Network (CAN) data bus.
The SCCM mounting housing also features an integral interconnect connector receptacle. This interconnect connects all of the inputs and outputs of the SCM to the vehicle electrical system through several terminal pins of the clockspring interconnect connector and the pass through circuits of the clockspring. The clockspring is connected to the vehicle electrical system through a dedicated take out and connector of the instrument panel wire harness.
The left multi-function switch provides the vehicle operator with a control interface for the following exterior lighting functions:
- Headlamp Beam Selection - The multi-function switch control stalk provides detent switching for selection of the headlamp HIGH or LOW beams.
- Headlamp Optical Horn - The multi-function switch control stalk includes momentary switching of the headlamp high beam circuits to provide an optical horn feature (sometimes referred to as flash-to-pass), which allows the vehicle operator to momentarily flash the headlamp high beams as an optical signalling device.
- Turn Signal Control - The multi-function switch control stalk provides both momentary non-detent (lane change) switching and detent switching with automatic cancellation for both the left and right turn signal.
The multi-function switch cannot be adjusted or repaired. If any function of the switch is ineffective, or if the switch is damaged, the entire SCCM mounting housing, SCM and multi-function switch unit must be replaced. Refer to MODULE, STEERING COLUMN CONTROL (SCCM), DESCRIPTION . The clockspring is available for separate service replacement.