door ajar

I have a 1993 t-bird and the "door ajar" alarm has started dinging continuously. I have no idea how this thing triggers or is shut off. Can anyone give me any ideas as to what to look for and where?

Thanks,
Dave

Check if the little tab by the inner portion of the door is broken.Its not attatched to the door,I think you know what im talking about.That would be the culprit in most cases.