wii docking charger

I put both remotes in the holder and then plug in the cord. one of the sides lights up but the other doesn't. How do i fix it? I've tried unplugging and plugging back in multiple times from both the wall and the charger itself. Ive looked at the remote and it seems nothing is wrong with them either. They work fine with batteries in them. So what do i do?
I tryed taking the strings out and it still didn't work. Only one side lights up even though both are in the dock. The light will light up and then turn off and the remotes wont be charged at all. The only other thing i can think of is that the charger it self is broken or the cord plugging it in is shot and needs another.