5 year old has irrational fear

My 5 year old boy started school last week. My son told me in the first week that he didn't like the red light in the bathroom  at school. I didn't think anything of this, but since then his teacher has said that he refuses to go to the bathroom to wash his hands or anything because he is so fearful of the red light. When I have picked him up at school a few days ago I went into the bathroom to see what was fearful of. There is a small red light at the entrance that is connected to the fire alarm. if the fire alarm goes off, it flashes but as far as i know is normally always off. I tried to encourage my son to go into the bathroom with me - to show him there was nothing to be afraid of, but he cowered in fear and refused. I told him that if he was brave and went into the bathroom he would get stars for his star chart and also a big surprise once he got 4 stars (toy reward). he is terrified and even this offer of reward is not enough to convince him to go into the bathroom. He can't go through the day at school without ever using the toilet. What should I do?

When he was little he had fears of handdryers, etc but these fears disappeared a while ago. This seems so irrational, but i am not sure how to resolve it.

Any suggestions would be helpful.

[margypops]

My thought is simply let it be in his control he will have to go unless he has started to wet himself, take a step back and let him go or not go , say nothing then see what happens. If there are further issues you may want to ask your Doctor what he thinks . Good Luck  and actually a lot of children dont like hand dryers thats not so unusual, I dont like them now .