i hav a 2000 explorer and just got a new head unit and bought a wiring harness to hook it up. on the wiring harness that's supposed to be plugged in to the truck there are 2 illumination wires, 1 of them is the illumination ground .Out of my new stereo there is only the illumination wire not an illumination ground wire. where do I put the illumination ground ? also i have 2 ground wires coming from my new deck 1 is 12v ground and the other is a chassis ground can i just hook them together?