Faulty Door censor on my alarm?

Hi,

I need help: My door's got a censor on it that triggers zone 1 in my alarm. It has stopped working. It's one of those button types that when the door closes it squishes the censor down and causes the system to know it is closed and conversely the button releases as the door eases off it and the alarm know the doors been opened. I opened the censor up and there is a yellow and a green wire hooked up to the censor. I rspliced the wire and put the back but nothing works. However if just one wire is in the alarm thinks the door is open but cant detect it when its closed and once i put another wire in (irrespective of color) the alarm goes back to now seeing the door. Can anyone tell me how to correct this. Is the whole wire for the censor useless or do i buy a new censor? or any other ideas?