Temperature light staying on in my Peugeot 106?

I have the temperature light staying on in my peugeot 106. I have changed the thermostate, both sensors, checked all wiring, checked coolant level, bled radiator, had a diagnostic test and checked all fuses. But annoyingly the light is still on!!! The fan is also on constantly.
Can anyone help?? does anyone know if I need to reset something or can you tell me which fuse goes to the dash light.