"Beeper" isn't the right word, but it's the best I can come up with. I mean the noise-emitting device that sounds when a door is open, seat belt not fastened, key in ignition, and so-forth.
I don't want to mess with the electronics, just find the noise-emitter and civilize it a little bit.... maybe spray some insulating foam over it or inject a little gunk into it....
It's somewhere behind the dashboard, but where? .... and what needs to be pulled off to get to it?