my story is a bit different. i DO use the rear cam. but i tried to modify the mount on the front unit (metal bracket instead of ball/socket). well, my new bracket warped the case enough to allow the front cover to make contact with the heat sink inside. the heat sink got hot enough to actually melt the plastic, which caused the vent holes to melt closed. suddenly there was no ventilation, so it overheated and died. then i bought a used 2ch setup from someone here on the forum. i left all the old parts (cables, power cord, mount, rear cam) in the car and just swapped in the main unit. everything's been fine since, so that's why i have a spare rear cam.