over head in black and white

I have an 7.2 pyle overhead monitor,with an in dash tv and a seperate dvd player,here is the problem that has me puzzled.when the tv is in tuner both the in dash and the over head are in color, but when a dvd is put in the over head turns into black and white, but the in dash stays in color,I have tried everything and cannot figure it out.Any suggestions.

It's the same wire going from the dvd player to the tuner to both the monitors,Like i said im puzzled with this one. The two monitors come in with color when the tuner is on and your wayching regular channels but when you put a dvd into the dvd player the in dash stays in color and the overhead is in black and white, cant figure it out.but thanks for the tips which i already did, If i figure it out i will post it.