- The large switch is a (plot) device in the Generation One continuity family.
The true details or capabilities of the device were not known except that it was linked to every Autobot and Decepticon to the point that, if switched off, the device would result in all the Transformers becoming inert.
The Transformers cartoon
The Quintessons used their new Decepticon allies to assault Cybertron while they secretly sent a commando team of Sharkticons into the depths of Cybertron to push the switch to the down position, which would have deactivated all the Transformers. The Sharkticons failed in their task because of Blitzwing and Rodimus Prime. However, the mad Galvatron thought that the switch was related to the Decepticon Matrix of Leadership, which was a Quintesson lie, and threw the switch himself. This stopped the Transformers war by stopping all the Transformers, leaving Cybertron back in the hands (or rather tentacles) of the Quintessons. That is, until Spike Witwicky used Rodimus's gun to destroy the switch, which reactivated the Transformers again, leaving the ever-irrational and maniacal Galvatron really ticked off at the Quintessons....