I am in Roaring Heights, I placed various things including a fire station. I have done the following steps in multiple towns with hitch.
I sent my sim on the first day to the firestation and joined the career and then asked for and received 5 days of unpaid leave. I worked his athletic and handiness skill at home (and rose to level 3-4 skill in each, and level 3 firefighting career) before returning him to the fire station in an attempt to maintain fire engine and alarm. He was able to do the fire engine without trouble, but when it came to the fire alarm, he flung his arms in the air and said there was something blocking him. (there wasn't anything that I could see). I then tried to upgrade the fire alarm, with the same result. I sent hm to each of the fire alarms at the fire station, and got the same result each time.
I have reset him, reset the town, restarted the save, cleaned the caches.
Any other suggestions for me - I don't play with mods at all.