Is that using the mod that adds the option to turn them on and off from the hotbar? You might want to contact the mod author in that case.
Otherwise I'm pretty sure you can still turn them on and off if you link an activation module to the Bobby AI, and use a wireless controller linked pair you control from another activation block on the main ship, linked to a inner ship remote so you can turn it all on and off from the hotbar.
The mod does save space and effort though, if you get it to work.
First things frist:
if you put the turret rail on your hotbar it's not for turning on or off turrets, but for actually controlling the aim and shooting.
There is a option in Bobby AI to actually aim manually with them.
If you want to turn on or off your turrets, you should install a mod from the ingame mod list (accessable in main menu) called "Turret Hotkey".
You'll get a little marker on the left side of your hotbar, showing you if turrets are on or off. you can turn them on by pressing 'J' and turn them of by 'L'
Turret on/off has been in StarMade for a very long time. When in the ships pilot core or on a station via a build block hit the DELETE key.
A menu opens with a long list of various things about your entity. Within this menu look for Rail System Collective or Rail Collective.
Even from before Rails were added to StarMade there was an option for turret control in this menu.
The option Activate all AI Turrets turns them on.
The option Deactivate all AI Turrets turns them off.
The option Reset all Turrets can only be found in this way and moves all Turrets to the default position.
After the GUI update a new option for Turret control was added in the build menu under Docks.
Under Stats open Docks and under AI click Turrets On or Turrets Off. There is no reset default position option here.
The radial menu also has no Turret controls and there is no way to bind keys other then with mods.
Some other things with Turrets:
If you use a shop to dock a ship with Turrets turn them OFF. The shops no power when docked makes it impossible for them to fire. But the AI still tries to move them resulting in extreme lag or a crash of the server. The sector may become unloadable preventing you from joining the game. This applies to all forms of Turrets including AMS Point Defence.
The option undock all needs extreme care. When done wrong it leads to massive entity collisions that will crash a server and make a sector unloadable.
When in build mode you can spawn a Turret from a blueprint directly onto a free Turret Rail Dock if the little circle in the center of your screen is pointing directly at the Turret Rail Dock block.