alarm ??

i have a 99 intrepid, How can I tell if my car has a factory alarm installed without the remotes. if it doesnt, then why does the horn sound when i hook up the battery?

When you lock the doors is there a flashing red LED on the center of the dash? If so you most likely have the alarm, if there is no red LED on the dash or anything that looks like a sharks tail sticking up from center of the dash then you do not have the alarm. To test, get in the car but do not put the key in the ignition, lock the doors with the door lock button and close the door, wait about a minute or 2 then open the door without unlocking the car, the headlights should flash and the horn will beep in time with the lights, get out and use the key to unlock the door to disarm.