the sensor on my alarm dosnt come on?

i have a veritas alarm system and it was working ok and all sensor was working , untill i did some pluming and water got it to one the sensors , and now none of the sensors light anymore , i have changed that sensor and still none of the come on ,the alarm it self works ok but when i enter my pin it just pleeps and dosent set , and none of the sensors lights come on any more , i am not sure what to do

kian
February 2008