I had the same issue with my rig... grainy pic. Usually this is caused by a less than wonderful connection. Make sure all your connections are snug, if they are you could have a bad ground connection at one of the cable ends. I had to replace one of the cable ends inside my rig with a new connector.
2012 Ford F250 Lariat FX4
2012 LaCrosse 318BHS w/4 Point Equal-i-zer Hitch
2 Wilderness Systems Kayaks
Nights Spent Camping in 2011 (19), 2012 (16)