Door / headlight / key in ignition warnings/buzzers inop

What is your question?

If memory serves, in a 2005 Scion xA, if you leave your key in the ignition, leave the headlights on, don't buckle-up, etc., there are audio alerts that should sound; I'm not hearing any for any of them. That being the case--and suspecting a blown fuse since _all_ those items are affected--I looked in the Owner's Manual and there's no mention (in the back) of a dedicated fuse for those items. What should be next in the troubleshooting chain to find the culprit?

How long has your 2005 Scion xA had this problem?

Months