Hi, Ive just finished installing a rearview 2 channel DVR to my car using the step by step instructions included. Problem is, when I put the car into reverse the rearview camera display switches on but the signal is very poor kinda distorted??? I went back to the rear reverse lamp and disconnected the black ground wire coming from the rear camera and the picture became crystal clear. My question is, do I even need to have the ground wire connected at the back or is it safe to just leave the red live trigger wire connected to the reverse power and forget about the ground wire. Ive also noticed that when I disconnect both the rear cameras red and black wires and just leave the video feed cable with the four white/yellow/red/black wires inside it connected to the aux in port on the dashcam the rear camera also works fine but i must manually change between front and rearview cameras. Im confused?? I donnot want to burn out the dvr unit or rear camera but I dont understand the need for the black rear camera ground wire and if I dont need it, why is it there???