The light on my hotpoint CDT00P tumble dryer will not go out?

The light on the Hotpoint Aquarius CDT00P won't go out. Water collects in the bottom of the back tray and does not go up into the removable water tank. I have checked the pipes and have cleaned the condenser float and resevoir. I believe it may be something to do with the pump? The machine works for a while and then the water light comes on although there is no water in the water tank.