[denverpete]

This has probably been covered a few times but basically here's how it works.

There is no "double-clicking" to lock and arm the alarm. On your first click your vehicle locks, your lights flash, and the light on the top of the dash will blink to show the alarm is armed. Unfortunately, Boxsters don't give a horn sound to let you know you've activated the alarm. If you get a horn when clicking the first time, you vehicle is letting you know that "something" is open. Generally the center console lid - but could be a door or trunk.

By double clicking and getting the horn, what you've actually done is turn off the interior sensor (in case you leave a pet in the vehicle).

Hope this helps...