I've added a command to turn them off, but they are activated by default and I can't change that.
Have you played the mod or not? Do the engine's have 'extinguishing functions' in 1.5? No
The fire engine's only had the hose connections, not a working cannon.
What he meant was that, did the original 1.5 model of the engine have the water cannon on it's model, not as a working feature. He already knew that.