One of my dds seemed scared of the tv when she was very young, and when she was around your ds' age she didn't like to watch it at all - she had worries over being scared by scary things on it, but also just in general she didn't like to sit in front of a tv and look at the screen. She was also extremely sensitive to noises from our vacuum cleaner etc. She was diagnosed with sensory issues through an OT eval and went through therapy which helped with the noise sensitivity at 5, and later at 7 was diagnosed with double vision and tracking issues, and it wasn't until after her eyes worked together that she started to actually enjoy tv. FWIW, we also couldn't take her to movies when she was your ds' age - she would scream soooooo so loud just at the thought of going to a movie. The one movie we ttook her to as a family I spent all but the first two minutes sitting in the hall with her as far away from the screen room as possible while her sibs and dad watched the actual movie. Even far removed and with walls in between she was terrified.
I think you mentioned in yr other post that you were considering an OT looking into sensory issues? It's possible that if there is something driving a sensory issue or related something - that might be the reason your ds is afraid of tv. It's difficult to tease out things like this with young children - once they are just a few years older and better able to communicate what they are feeling inside puzzles like this become easier to understand.
Best wishes,
polarbear
