I recently prurchased a used 2000 911 Cab. with what appears to be a factory installed radar detector font & rear. There are no instructions in any manual I received and the original owner is unknown. Is there a way to turn the unit on & off? Does anyone have any idea what fuse controls the units power. The prior owner had it disconnected because it annoyed him, going off constantly. However, I want everything in the car to operate correctly and want to avoid the dealer looking for the problem if possible.