why is my coolant temp light on and goes out at 90°

[Yaza01]

hi all my coolant light comes on even if i drive it and the coolant gets up to 80° if i switch it off and on the light will still remain and stays on until it reaches 90° once it reaches 90° if i switch car off and on the light will not come on
please help changed coolant level sensor and washer bottle sensor cheers

 

[streethawk]

Coolant low so the light comes on. Once warm the water expands thus making level higher and extinguishing light. Coolant should be at the top of the clear bit of tank where it turns into black plastic when hot.

 

[Yaza01]

fan module was the problem