2004 Mercury Grand Marquis LS Ultimate Edition cruise control failed

What is your question?

Bought a 2004 Mercury Grand Marquis LS Ultimate Edition used in Sep 2012. Cruise control buttons are on the steering wheel. PROBLEM: Cruise control buttons on steering wheel have never worked since day one. Cruise control does not function. CRUISE indication does not appear on instrument panel. What part is bad? How much is it? Where is it? How do I put it in? Thanks!