First post, as always starts with a question...
I have a triple beep in my 3.2 V6 Brera from '06. The beeps are about 5 seconds to 10 seconds apart, there are no messages prompting on the read-out in the dials. Oil is full, the handbrake is fully depressed, as I tried that after reading similar issues. There is also no issue with the weight sensor on the passenger seat. No warning lights come up.
So in summary, 3 beeps, 5 seconds apart, no warnings lights, and seemingly no reason for it.