Appears my display screen on F7010bt only displays when the car is in reverse, it goes blank when I put it in drive.  The system is on, I can hear radio, etc. Any ideas as to why this is happening?

problem solved

What was the problem????   mine has dark screen most of the time.   Don't have back up cam,  radio plays, blue tooth works, but the radio doesn't come back on after phone call,  have to turn key off and back on to get radio back.   CD and memory card show music files playing, but no sound.   Think i'm gonna scrap it since I can't get any help with it