if your confident enough opening it up just wiping the contacts might fix it, has it had anything spilt in it by any chance?not sure if this is appropiate here but:
Can a 3ds d-pad that only works in 1 direction be fixed at home? Only the left button works...
and is it only on the homescreen its not working?
oh do you mean the circle pad or the d-pad, i have seen a few people refer to the circle pad as the dpad too(for some reason )