I have a parts car coming this week that has sensors if you need one let me know. If it were bad the light would go off to tell you but if you know its looking bad I would not wait for the light to come on. Best case scenario is that it will not go off when you need it. Worst case scenario is it triggers while your just driving down the highway and after having mine pop 2 weeks ago trust me you want it to go off when you need it and not when you don't...