Several different types of steering wheels are used on GM W-Body vehicles, depending on model year, trim level and options. Many steering wheels will have remote radio switches (also called redundant radio switches) built into the steering wheels. Cruise control switches as well as horn and air bag functions are all built into the steering wheel.
One important component just under the steering wheel is the SIR coil. Since so many wires run to the face of the steering wheel including the all-important air bag connections, a special wiring device called the SIR coil is used to allow the steering wheel to turn freely yet, still provide reliable wiring connections through a "ribbon cable" arrangement. Care must be used to always center the front wheels and lock the steering column when working on the steering wheel and related components. The SIR coil assembly will become "uncentered" if: