Hi Micksue, welcome to the forums! (Sundancer forgot his manners
)
Several possibilities. Substandard splitter is a common problem, as are not connected cables, or misconnected cables. I am not familiar with your particular unit so hopefully someone that has one can chime in.
Best bet is to try and track the cables to see where they go. A signal feed generator with the coax adapter might prove helpful in this situation. Typically the splitters are hidden in the walls behind the wall plates where the TV's are hooked up. Though they can be anywhere.
Aaron