i have the battery cable unhooked from the battery and starter, why am i still

With the test light lead hooked up to battery positive, touching the probe end to any point on the vehicle that can provide a ground OR resistance is going to light up the light every time! .. If you'll look, the positive cable likely has another lead that still hooked up. .. Test light don't care which way it hooked in a circuit, it only need voltage to light up. With anything on the car turned on, It will do the exact same thing if hooked the same way to the negative side!.. What are you testing?