Alarm Going Off

[daveplot]

My father's 03 Boxster's alarm keeps going off at night, randomly. Where can I start diagnosing the problem? It has a soft top.

I've searched the forums and found the option of pressing the lock button twice to lock but disable the alarm, or pulling the horn fuse temporarly.

Thanks for your help!

[986FortyEight]

my 98 would do the same thing randomly.
Loose connector somewhere behind the radio I was told by the mechanic. 5mins.