A kind person replied to my post with an answer. I'm posting their answer here to help others.
--CaptWiggum
Marcella Wegiel Fri, Sep 16, 2005 at 1:37 PM To: snipped-for-privacy@gmail.com
Thanks for replying. After emailing you I continued to search and found the answer. This is what happens when the alarm has been triggered. The computer isn't smart enough to realize if the key was used or not. Trigger the alarm, and the truck will make sure you know about it for the next few days. If it ever happens again, lock the doors with the key fob as usual. Unlock the door using the key and open it, triggering the alarm again. Turn it off by pushing the unlock button on the key fob. This should reset the computer. Or you can just a wait a few days for the alert to time out. Thanks!
-Matt