Does anyone know the problem and how to sort it?

I have a vauxhall zafira elegance 1.8 t reg 1999 petrol and on the dash i have an orange warning light that has come on constantly for a while now. It looks like a picture of a radiator with what looks like a fan/star in the middle of it, does anybody know what this is and why it is constantly on and if so how do i possibly get the problem sorted out? I would be very grateful for any feedback many thanx