What controls the audible alerts?

[ptwink]

So, a couple years ago, I noticed that my turn signals would stop making noise. And then randomly, they would start again. Next, my "you left your headlights on" noise stopped. Now my "you left the keys in the ignition" and "seat belt is not on" noise all have stopped. Is there one relay or speaker that controls all of these functions? A circuit board? Where would I find more information on it? Can I replace it myself?