On my Vizio my Wii is showing up in greyscale, but if i switch my Wii cords in place with my 360 cords in the exact same posistion my 360 shows fine.

On the back of Tv the plugins are labeled accordingly
1st- (Green) and says Y
2nd- (Blue) says Pb/Cb
3rd- (Red) says Pr/Cr
4th- (White) says L
5th- (Red) says R