I just picked up a truck that has the Z3 installed. The guy told me it quit working after the truck battery went dead. Today i took the unit out and installed a AV cable and all of the sudden the back up camera started working. once i installed the unit back it was no longer working. when i put the truck in reverse the screen changes and says "images may be reversed" but there is no image. 

thinking there was a loose connection i traced the wires from the back of the unit but didn't see anything obvious. 

any ideas?

thanks. this thing seems intense. looking forward to seeing what it will do. 

There is not enough information in your post to remotely troubleshoot. Why did you take the unit out to install an AV cable if the head unit was not working? Does everything else work now except a blank screen when in reverse?

Check for 12 volts or loose ground on the input module.