Haunted alarm system?
 

2002 986

About every hour you get two beeps from the alarm horn (whether driving or parked). The button on the dash for "lock" is illuminated - depressing it in either direction makes the alarm beep twie again - but light never goes out.

Doesn't appear to be disabling the ignition.

Exorcist? Or just a big hammer... :)

I believe that two beeps is the alarm diagnostics signal that something is wrong with the alarm. Prabably have to hook it up to the expensive factory computer to diagnose.