What do you mean it only works when its sunny?

Mine basically if i hoon it too hard round a bend or a roundabout the light on the dash flashes and it cuts the revs, well the car feels like its hit a brick wall/lost power, turn it off so the light is constantly on and you can wheel spin it into rounds abouts and do what ever you like in the wet its pretty sketchy with it turned off mine is low though so i can throw it around more than a standard one which just makes the ESP even more reactive if its on