Sorry to hear that fear of darkness prevents you from sleeping without the TV on. As the fear has been through your childhood, did you ask your parents about the precipitating factor? Do they now what started it? Do you have the sound of the TV on? Or just the screen with light on? You may want to engage in prayers or meditation depending on your belief system. I would also suggest you consider seeing a licensed psychologist, who specializes in hypnotherapy, to get to the roots and origins of the fear. Heal from it and release it so you can live a life without the fear of darkness.
Dr. Lata Sonpal
The following link should give you some additional cues
There are some apps you might want to download to will be useful if you have a smart phone. The apps are: CALM and PEACE