On the lower side of the door jam (torwads the rear of the door) there should be a little push button switch thingy. if not there will be a hole in the door jam. eathier way, this little button thingy is what activates the chime/light. (door closes, pushes switch in, breaks the electrical path to the light/chime, so it shuts off.) there is a little plug on the back, check to make sure its plugged in. i personally disconnected the plug on the back of mine because its (the chime thing) annoying as shit, but its just as easy to plug it back in if thats whats wrong.