<human>: Can you condense the text into three sentences or less?

Have a 3 year old Chihuahua-Papillon rescue who is spunky and hilarious and the love of my life. I've been with him for a year, my SO has had him for a year and 9 months.  
He gets spooked by a lot of random things, and we've very patient with him, but a few days ago we had to turn the wall-unit AC on for the first time and since then he's been PETRIFIED to enter our bedroom after dark.  
He's fine running all over our room happily during the day, but he won't even accept treats on our bed at night now, just tries to get out of the room as fast as possible.    
  
I miss sleeping with my best friend. I hate seeing him scared and uncomfortable. He's too upset to come in the room, but it also upsets him to sleep without us. He stares at us from the couch in the living room all night and it would be hilarious if it weren't so sad and pathetic.  
  
He has experienced multiple wall-unit AC's in his life, I've slept with him numerous times in my old house with louder, windier AC's and it has never been a problem.  
  
How do I reaccustom him to life in our room? How do I help him get over whatever spooked him so terribly this time vs. any other time we've turned it on in other houses?  
I led him to the room with meat today and got him as far as the threshold of the door and then my SO made a little noise and he got spooked and started trembling and ran away.  
I have no lack of patience, just a lack of knowledge. Help me help him feel comfortable in his home again.
<bot>: dog is petrified of AC, didn't used to be, how do I help him feel comfortable in my room again?