I had this issue, too. I didn't have the cable inserted all the way. There is a small click as well as the light will blink when inserting it in all the way but it will continue to blink while putting pressure on the cable if it is not in all the way. There is no blink if it is inserted completely. It took me going back through the install process to finally figure it out after about half an hour of frustration... even though you've probably figured it out by now. Hope this helps somebody, though!