Clock Spring
"Sliding contact" is a misnomer. The older horn contacts were sliding, but a more-stable connection was needed for airbags, which is why the clock spring was invented. It's a long ribbon of plastic with metal traces coiled like a clock spring that provides a wire-like path from the stationary steering column to the rotating steering wheel. Unfortunately, over a few years, the traces either wear through or crack, causing airbag, cruise control, horn, and radio malfunctions.
For more info, see this album:
