how can i fix a problem with a redring expressions 570 elec shower?

I had this shower installed about two years ago and its worked fine up to now. What's happening now is that the little red light on the pull-cord switch is flickering minutely - it appears ok, but on close inspection its flickering. When i turn the shower on, nothing happens (except for a light cold shower from the water tank, caused by gravity), and the little red light goes out altogether! I've checked all the connections, both inside the shower and on the cord switch, and there's no loose wires or connections. HELP!!