could just be dirty inside. take the button apart. (easy; the outer ring is just a piece of plastic with flexible barbs to retain it, just pry it off and it'll go back on later) the contacts are two pieces of copper (gold-plated, maybe?) zig-zagged across a plastic disc. The switching material is a piece of conductive rubber on the button. Clean the disc, clean the little "rrrrrrrrubbah biskIT!!!!" (I had to do it) with some rubbing alcohol and reassemble. The buttons inside your alarm remote, and under your computer's keyboard are the same way. CLEAN'EM ALL!