Added rear camera, this tab only has front camera

I have rca voy 2. Screen broke and replaced it with screen from voy 3..so since my voy 2 only has front camera i decided to add the voy 3' s rear cam and just put the 3's back on it so i can have rear facing cam. It all interchanged but my tab says "cant connect to camera close all apps that may be using camera. Can i add second camera or do i need to put it back the way it was?