I purchased a remote switch for my D3100, at $30, just before Christmas, and the other day without warning it just stopped working. not knowing if it was the switch or my camera, I took the switch back toto have the switch checked with one off their of the shelf cameras. I did not have a receipt. Yes it was determined it was the switch. To my surprise the salesman just handed me a new one with a Happy Easter.
PS. I am not really happy with the remote, the cable is too short. I would have preferred a wireless one but at the time, I was in a hurry and the salesman told me, it was the only one available for the camera of that age. ( guess it was the only one available in store, for a camera of that age )