indesit idc 75 water tray full light stays on even when the tray is empty?

hello i am trying desperately to fix this, please help. I have opened the back and cleaned all the fluff from the machine. I have took off the black and clear water pipes and cleaned them,thinking they are blocked. At the back where the water collects and the float for the on/off switch for the water is ive checked.I think when the water level is full in this water tray at the bottom then switches on the light which causes the dryer not to heat upCan anyone please advise how to solve thisplease.