Can you send some pictures? Sound like maybe its for lightning and the light on the dvd player but yet again I never heard of a dvd player having lights. So I am not sure. Are you sure its not just the psu switch? there are 2 wires, so has to be positive and negative. If one is going to a lighting configuration, then the other has to be going to ground, don't know why ground is going to a dvd player.