You either need new battery's or need to

resynchronize it you do this by:

you need to sync the controller that is going to be used

open the battery casing. press the little red
button inside until the 4 lights on the front flash

then go over to the console and open the SD card cover on the front and press that little red button

then the controller is synced and your light will correspond to Wat player you are

hope this helps