I just received a new The Directtv-RC64RBK Universal Back Lit Remote. I put the batteries in, and programmed the remote to my Vizio and a HC-20 Receiver. I did not see the back light during programming of the remote. Later on, when I was showing the new remote to my wife, the back lighting started working. Then, later, it stopped working. The enclosed manual said nothing about back lighting that I could find. Is there something I don't understand about the remote? Should the key pad be lit with every touch of any key? Is it intermittent or defective? What do you recommend I do or try?