Quote Originally Posted by aratti View Post
X5-3 point goes to a pic pin. Is it an input? If yes and you have nothing connected to the terminal, then you have to ground or pullup also X5-3
Another vote for pull-up or pull-down (some high but reasonable value would be OK). Floating input will see your LED transient (voltage/current change) and interpret that as an input signal (=working as a sensitive receiver).

-Gusse-