lose sound after camera turns on. Turn the car on and I have sound but if I either put the car in reverse or drive (either way the camera turns on)I won't get any sound. When in park or neutral I have sound but anytime I put it in gear after passing reverse I get nothing. No radio, cd, or sd card. The screen shows that it's playing but I can't seem to figure it out. Any assistance would be greatly appreciated. 

The only way that makes sense is if your wiring is totally messed-up. Start with checking the Mute wire, backup wire, and parking brake wire. Was this a used unit? The previous owner may have moved the mute wire to do the Parking Brake Bypass. 

Do you have steering-wheel controls connected?

BTW, please stop spamming the same post. Your questions won't get answered any quicker.