Mate, I would recommend draining the fuel at teh bottom of the fuel filter. The light is indicating that you have water in your system. DO NOT drive the car in this condition until you have confirmed that the fuel is not contaminated. If that is not the cause then check the connection of the wires at the fuel filter, if they are connected correctly then remove the filter assembly and then remove the filter. Check the float is not damaged and the reconnect the wiring to the housing. Check to see if the light is off on the dash with teh float in the lower position. If it is, then check that the light goes off, when you lift the float, and goes out again when you lower it.