Mystery alarm

my truck has recently started “beeping” after I start it up and keeps beeping every 30 min. during travel, any idea what the beeping is and how do I put an end to it? thanks, Joel

2002 f150 6cyl 5speed manual

Your isnt the only one http://www.google.com/search?q=2002+f150+beep+every+30+minutes&ie=utf-8&oe=utf-8&aq=t&rls=org.