I'd say it's most likely a loose or fried RCA video (yellow) connector or wire. I have the same unit as yours in my 2009 Greyhawk. If you do have the manual, there is a set of pins supplied needed to remove the LCD from the four mounts accessed by pin holes on the corners. Otherwise a very small Allen wrench or even large pin should do it. My Cable TV setup has a single coax connector spit three ways. The DVD player uses RCA connectors, two audio (red and white) and one video (yellow) which were electrical taped together. (Not the finest quality RCA connectors either). My DVD was fading into B & W, the mail video RCA was not snug fitting into the female on the unit itself. I crimped it a bit with a pair of plyers to fix.