Why does my dehumidifer not work?

If it is not running because it thinks the bucket is full even when it isn't, the problem is that the float is broken or jammed. A replacement is no longer available, but you can find the small switch and tape it so it always stays on. It won't shut off when the bucket is full, but it will run. This assumes all the other panel lights come on properly - you didn't provide much detail about what works and what doesn't work.